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.
l1 = [int(x) for x in input().split(":")]
finalh,finalm = l1[0], l1[1]
l2 = [int(x) for x in input().split(":")]
diffh, diffm = l2[0], l2[1]
finalsum = finalh*60+finalm
diffsum = diffh*60+diffm
#print(finalsum,diffsum)
k = (finalsum-diffsum)%(24*60)

hour = int(k/60)
minute = k%60
if hour ==0:
    hour = "00"
elif hour <10:
    hour = "0"+str(hour)
else:
    hour = str(hour)
if minute ==0:
    minute = "00"
elif minute <10:
    minute = "0"+str(minute)
else:
    minute = str(minute)
print(hour+":"+minute)
