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.
s = str(input())
h = int(s.split(":")[0])
m = int(s.split(":")[1])
t = str(input())
h1 = int(t.split(":")[0])
m1 = int(t.split(":")[1])
ans_h=0
ans_m=0
if m>=m1:
    ans_m = m - m1
else:
    ans_m = m+60 - m1
    if h!=0:
        h = h-1
    else:
        h = 23
if h>=h1:
    ans_h = h-h1
else:
    ans_h = h + 24 - h1
ans_h = str(ans_h)
ans_m = str(ans_m)
if len(ans_m)==1:
    ans_m = '0'+ans_m
if len(ans_h)==1:
    ans_h = '0' + ans_h
print(ans_h+":"+ans_m)