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.
fir = input().split(':')
sec = input().split(':')

ah = int(fir[0])
am = int(fir[1])
bh = int(sec[0])
bm = int(sec[1])

if(ah<bh or(ah==bh and am<bm)):
    ah=ah+24
ah=ah-bh
am=am-bm
if(am<0):
    ah=ah-(-am)%10-1
    am=60+am
print('%02d:%02d'%(ah,am))