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()
s2 = input()
time1, time2, ls1, ls2, ans = '', '', [], [], [':']
for i in range(len(s1)):
    if s1[i].isnumeric():
        time1 += s1[i]
    if not s1[i].isnumeric():
        ls1.extend([time1, s1[i+1::]])
for i in range(len(s2)):
    if s2[i].isnumeric():
        time2 += s2[i]
    if not s2[i].isnumeric():
        ls2.extend([time2, s2[i+1::]])
hours = int(ls1[0]) - int(ls2[0])
if hours < 0:
    hours = 24 + hours
if len(str(hours)) == 1:
    ans.insert(0, '0'+str(hours))
else:
    ans.insert(0, str(hours))
minutes = int(ls1[1]) - int(ls2[1])
if minutes < 0:
    minutes = 60 + minutes
if len(str(minutes)) == 1:
    ans.append('0' + str(minutes))
else:
    ans.append(str(minutes))
print(''.join(ans))


