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.
from sys import stdin ,stdout 
input=stdin.readline
def print(*args, end='\n', sep=' ') -> None:
    stdout.write(sep.join(map(str, args)) + end)

cur=input().strip() ; curHou=int(cur[:2]) ; curMin=int(cur[3:])
time=input().strip() ; tiHou=int(time[:2]) ; tiMin=int(time[3:]) ; cond=False
if curMin>=tiMin:
    sMin=curMin-tiMin
else:
    sMin=60+(curMin-tiMin) ; cond=True

if curHou==0:curHou=24
if tiHou==0:tiHou=24
if curHou>=tiHou:
    sHour=curHou-tiHou
else:
    sHour=24+(curHou-tiHou)
if cond :
    if sHour==0:
        sHour=23
    else:
        sHour-=1
sHour=str(sHour)
if len(sHour)==1:
    sHour="0"+sHour
sMin=str(sMin)
if len(sMin)==1 :
    sMin="0"+sMin
print(sHour+":"+sMin)




