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.
t1 = list(input())
t2 = list(input())

h1 = int(t1[0] + t1[1])
m1 = int(t1[3] + t1[4])
h2 = int(t2[0] + t2[1])
m2 = int(t2[3] + t2[4])

if m1 < m2 :
    m1 += 60
    h2 += 1

if h1 < h2 :
    h1 += 24
h3 = str(h1 - h2) 
m3 = str(m1 - m2)

if len(h3) == 1 :
    h3 = "0" + h3
if len(m3) == 1 :
    m3 = "0" + m3
print(h3 + ":" + m3)