George woke up and saw the current time *s* on the digital clock. Besides, George knows that he has slept for time *t*. 

Help George! Write a program that will, given time *s* and *t*, determine the time *p* when George went to bed. Note that George could have gone to bed yesterday relatively to the current time (see the second test sample).
The first line contains current time *s* as a string in the format "hh:mm". The second line contains time *t* in the format "hh:mm" — the duration of George's sleep. It is guaranteed that the input contains the correct time in the 24-hour format, that is, 00 ≤ *hh* ≤ 23, 00 ≤ *mm* ≤ 59.
# a = input()
# b = input()


# def change_list_string(l):
# 	s = ""
# 	for i in l:
# 		s+=i
# 	return s
	
# s1 = []
# for i in a:
# 	s1.append(i)
	
# # flag = 0
# # for i in range(len(s1)-1):
# # 	for j in range(i+1,len(s1)):
# # 		s1[i],s1[j] = s1[j],s1[i]
# # 		s = change_list_string(s1)
# # 		# print(s)
# # 		if (s==b):
# # 			print("YES")
# # 			flag = 1
# # 			break
# # 		else:
# # 			s1[i],s1[j] = s1[j],s1[i]
			
# # if (flag==0):
# # 	print("NO")

# index_a = -1
# index_b = -1
# letter_a = ""
# letter_b = ""
# flag = 1
# for i in range(len(a)):
# 	if (a[i]==b[i]):
# 		flag = 1
# 		continue
# 	elif (a[i]!=b[i]):
# 		flag = 0
# 		if (a[i]==letter_b and b[i]==letter_a):
# 			flag = 1
# 			continue
# 		else:
# 			flag = 0
# 			letter_a = a[i]
# 			letter_b = b[i]
# if (flag):
# 	print("YES")
# else:
# 	print("NO")    
    
# n,m = map(int,input().split())
# align = ""
# line_arange = ['NO' for i in range(300)]
# k = n-1
# l = m-1
# pos = 2
# line_arange[0] = 'B'
# for i in range(k):
# 	line_arange[pos] = 'B'
# 	pos+=2
# line_arange[1] = 'G'
# pos = 3
# for i in range(l):
# 	line_arange[pos] = 'G'
# 	pos+=2
# for i in line_arange:
# 	if i!='NO':
# 		align+=i
# print(align,end = "\n")	


# n = int(input())
# arr = []
# for i in range(n):
# 	arr.append(i)

# res = []
# for i in range(0,len(arr)-1):
# 	for j in range(i+1, len(arr)):
# 		if (arr[i]==arr[j]):
# 			res.append([i+1,j+1])
		
# if (len(res)>0):	
# 	for i in res:
# 		for j in i:
# 			print(j,end=' ')
# 		print()
# else:
# 	print(-1)


# line = input()
# res = []
# for i in line:
# 	if i in '{ } ,  '.split(' '):
# 		continue
# 	if i==' ':
# 		continue
# 	res.append(i)
# res = set(res)
# print(len(res))

# n,m = map(int, input().split())
# print(n,m)



# n = int(input())
# x = input()
# y = input()
# x = x.split(); x_m = int(x[0]); x = x[1:]
# y = y.split(); y_m = int(y[0]); y = y[1:]
# if (len(x)>0 and len(y)>0):
# 	x = list(map(int,x))
# 	y = list(map(int,y))
# 	x.sort()
# 	y.sort()

# 	x = list(set(x + y))
# 	# print(x)

# 	s = sum(x)
# 	y = sum([i for i in range(1,n+1)])

# 	if (x[-1]==n and s==y) :
# 		print("I become the guy.")
# 	else:
# 		print("Oh, my keyboard!")
# elif (len(x)>0):
# 	x = list(map(int,x))
# 	x.sort()
# 	x = list(set(x))
# 	s = sum(x)
# 	y = sum([i for i in range(1,n+1)])
# 	if (x[-1]==n and s==y) :
# 		print("I become the guy.")
# 	else:
# 		print("Oh, my keyboard!")
# elif (len(y)>0):
# 	y = list(map(int,y))
# 	y.sort()
# 	y = list(set(y))
# 	s = sum(y)
# 	x = sum([i for i in range(1,n+1)])
# 	if (y[-1]==n and s==x) :
# 		print("I become the guy.")
# 	else:
# 		print("Oh, my keyboard!")
		
# else:
# 	print("Oh, my keyboard!")


# n = input()
# gift1 = int(n[:-1])
# # print(gift1)
# gift2 = int(n[:-2] + n[-1])
# # print(gift2)

# n = int(n)

# if (gift1>=n and gift1>=gift2):
# 	print(gift1)
# elif (gift2>=n and gift2>=gift1):
# 	print(gift2)
# else:
# 	print(n)


# i = len(s)-2
# flag = 0
# if (s[i].isalpha()==1):
# 	if ((s[i] in 'A E I O U a e i o u Y y'.split())):
# 		print('YES')
# 	else:
# 		print('NO')
# else:
# 	while (s[i].isalpha()!=1):
# 		if ((s[i] in 'A E I O U a e i o u Y y'.split())):
# 			print('YES')
# 			flag = 1
# 			break
# 		i-=1;
# 	if (flag == 0):
# 		print("NO")


# s = input()
# l = []
# for i in s:
# 	if i.isalpha()==1:
# 		l.append(i)
# l = l[-1]
# if ((l in 'A E I O U a e i o u Y y'.split())):
# 	print('YES')
# else:
# 	print("NO")

# n = input()
# d = {'h':[],'l':[],'e':[],'o':[]}
# for i in range(len(n)):
# 	if (n[i]=='h'):
# 		d['h'].append(i)
# 	elif (n[i]=='e'):
# 		d['e'].append(i)
# 	elif (n[i]=='l'):
# 		d['l'].append(i)
# 	elif (n[i]=='o'):
# 		d['o'].append(i)

# max_h = 0
# max_e = 0
# max_l1 = 0
# max_l2 = 0
# max_o = 0
# for i in range(len(n)):
# 	if (n[i]=='h'):
# 		max_h = i
# for i in range(max_h+1,len(n)):
# 	if (n[i]=='e'):
# 		max_e = i
# for i in range(max_e+1,len(n)):
# 	if (n[i]=='l'):
# 		max_l1 = i
# for i in range(max_l1+1,len(n)):
# 	if (n[i]=='l'):
# 		max_l2 = i
# for i in range(max_l2+1,len(n)):
# 	if (n[i]=='e'):
# 		max_o = i
# d = [max_h,max_e,max_l1,max_l2,max_o]
# print([max_h,max_e,max_l1,max_l2,max_o])


# if (d[0]<d[1] and d[1]<d[2] and d[2]<d[3] and d[3]<d[4] and d[4]>d[0]):
# 	print("YES")
# else:
# 	print("NO")

# n = int(input())
# min_age = 0
# l = [ 'ABSINTH', 'BEER', 'BRANDY', 'CHAMPAGNE', 'GIN', 'RUM', 'SAKE', 'TEQUILA', 'VODKA','WHISKEY', 'WINE']
# for i in range(n):
# 	ele = input()
# 	if ele.isalpha():
# 		if (ele in l):
# 			min_age+=1
# 	else:
# 		if (int(ele)<18):
# 			min_age+=1
# print(min_age)

# n = int(input())
# d = {}
# for i in range(n):
# 	s = input()
# 	if s not in d:
# 		d[s] = 1
# 	else:
# 		d[s]+=1
		
# k = list(d.keys())
# v = list(d.values())
# if (len(v)>1):
# 	if (v[0]>v[1]):
# 		print(k[0])
# 	else:
# 		print(k[1])
# else:
# 	print(k[0])


# import numpy as np

# l = np.linspace(1,10,100)
# print(l)

# t = int(input())
# ans = []
# for i in range(t):
# 	num = input()
# 	sum1 = 0
# 	for j in range(0, 3):
# 		sum1+=int(num[j])
# 	sum2 = 0
# 	for j in range(3, 6):
# 		sum2+=int(num[j])
# 	if (sum1==sum2):
# 		ans.append("YES")
# 	else:
# 		ans.append("NO")
# for i in ans:
# 	print(i)


# def checkSpell(s):
# 	if (len(s)!=5):
# 		return "NO"
# 	for i in s:
# 		if i not in "T i m u r".split():
# 			return "NO"
# 	return "YES"

# l = ['H', 'e', 'l', 'l', 'o', '\r', '\n', '\r', '\n','\r', '\n', 't', 'h', 'i', 's', '\r', '\n', 'i', 's', ' ', 'm', 'y', ' ', 'w', 'o', 'r', 'l', 'd']
# m = [l[0]]
# mIndex = 0
# i = 1
# while (i<len(l)):
# 	if (m[mIndex]=='\n' and l[i]=='\r'):
# 		i+=2
# 	else:
# 		m.append(l[i])
# 		i+=1
# 		mIndex+=1
# print(m)

# import numpy as np
# import pandas as pd
# np.random.seed(105)
# data = np.random.randn(5,4)
# # print(data)

# df = pd.DataFrame(data, columns='x y z w'.split())
# print(df)
# print(df[df['x'].apply(lambda x : x<0)].reset_index())


s = input()
t = input()

s = s.split(':')
t = t.split(':')

diffHours = int(s[0]) - int(t[0])
diffMinutes = int(s[1]) - int(t[1])
# print(diffHours, diffMinutes)


if (diffMinutes<0):
	diffMinutes = -diffMinutes
if (diffMinutes<10):
	diffMinutes = '0' + str(diffMinutes)
	
if (diffHours<0):
	diffHours = 24 + diffHours
if (diffHours<10):
	diffHours = '0' + str(diffHours)



print(f'{diffHours}:{diffMinutes}')

# print(s,t)