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.
# Hello World program in Python
    
s1 = input()
s2 = input()
hours =int(s2.split(":")[0])
minutes=int(s2.split(":")[1])
curr_hour =int(s1.split(":")[0])
curr_min=int(s1.split(":")[1])
ans_min=0
#print(hours,minutes,curr_min,curr_hour)
ans_hour=0
if curr_min<minutes:
    ans_min=curr_min-minutes+60
    ans_hour=-1
else:
    ans_min=curr_min-minutes
if curr_hour<hours:
    ans_hour=curr_hour-hours+24
else:
    ans_hour=curr_hour-hours
ans=""
if ans_hour<=9:
    ans=ans+'0'
    ans=ans+str(ans_hour)
else:
    ans=ans+str(ans_hour)
ans=ans+':'
if ans_min<=9:
    ans=ans+'0'
    ans=ans+str(ans_min)
else:
    ans=ans+str(ans_min)
print(ans)