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.
h=[]
m=[]

for _ in range(2):
    x,y = list(map(int, input().split(':')))
    h.append(x)
    m.append(y)
    
h[0]=h[0]-h[1]
m[0]=m[0]-m[1]

if m[0]<0:
    h[0]-=1
    m[0]+=60
    
if h[0]<0:
    h[0]+=24
    
if h[0]>=0 and h[0]<=9:
    h[0]='0'+str(h[0])
    
if m[0]>=0 and m[0]<=9:
    m[0]='0'+str(m[0])
    
print(f"{h[0]}:{m[0]}")