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.
a = input()
q1, q2, q3, q4 = int(a[0]), int(a[1]), int(a[3]), int(a[4])
b = input()
w1, w2, w3, w4 = int(b[0]), int(b[1]), int(b[3]), int(b[4])
ww = (q3*10 + q4) + (q1*10 + q2)*60
qq = (w3*10 + w4) + (w1*10 + w2)*60
s = ""
if (ww - qq) > 0:
    if(ww - qq) // 60 > 9:
        d = str((ww - qq)//60)
        s += d
    else:
        s += "0"
        d = str((ww - qq)//60)
        s += d
    s += ":"
    if (ww - qq) % 60 > 9:
        d = str((ww - qq)%60)
        s += d
    else:
        s += "0"
        d = str((ww - qq)%60)
        s += d    
else:
    if(ww - qq + 1440) // 60 > 9:
            d = str((ww - qq+ 1440)//60)
            s += d
    else:
        s += "0"
        d = str((ww - qq+ 1440)//60)
        s += d
    s += ":"
    if (ww - qq + 1440) % 60 > 9:
        d = str((ww - qq + 1440)%60)
        s += d
    else:
        s += "0"
        d = str((ww - qq + 1440)%60)
        s += d        
print(s)
    