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, t = input(), input()
h1, m1, h2, m2 = int(s[0:2]), int(s[3:5]), int(t[0:2]), int(t[3:5])
m, h = m1 - m2, h1 - h2

if (m1 < m2):
    h1 -= 1
    m=(60+m1)-m2
if (h1 < h2):
    h = 24 +  (h1-h2)

m, h = str(m), str(h)

if (int(m) < 10):
    m = '0' + m
if (int(h) < 10):
    h = '0' + h
print(h + ':' + m)
