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.
S1 = input().split(':')
S2 = input().split(':')

h1 = int(S1[0])
m1 = int(S1[1])
h2 = int(S2[0])
m2 = int(S2[1])

if h2 + m2 == 0:
    print(S1)

else:
    if h1 + m1 == 0:
        h1 = 24
    cur = h1 * 60 + m1
    use = h2 * 60 + m2
    cur -= use
    h1 = cur // 60
    m1 = cur % 60
    if h1 < 10:
        h1 = "0" + str(h1)
    if m1 < 10:
        m1 = "0" + str(m1)
    print(str(h1) +':' + str(m1))
        
        