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.
woke_hr, woke_min = map(int, input().split(":"))
dur_hr, dur_min = map(int, input().split(":"))
st_sleep_hr, st_sleep_min = 0, 0

if woke_min < dur_min: st_sleep_min = (60 + woke_min) - dur_min; dur_hr += 1
else: st_sleep_min = woke_min - dur_min

if st_sleep_min in range(0, 10): st_sleep_min = "0"+str(st_sleep_min)
else: st_sleep_min = str(st_sleep_min)

st_sleep_hr = (woke_hr - dur_hr) % 24

if st_sleep_hr in range(0, 10): st_sleep_hr = "0"+str(st_sleep_hr)
else: st_sleep_hr = str(st_sleep_hr)

print("".join([st_sleep_hr, ":", st_sleep_min]))