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 = input()   # current time
t = input()   # duration of sleep

# Convert s and t to minutes
s_minutes = int(s[:2]) * 60 + int(s[3:])
t_minutes = int(t[:2]) * 60 + int(t[3:])

# Calculate the time George went to bed, in minutes
p_minutes = s_minutes - t_minutes
if p_minutes < 0:
    p_minutes += 24 * 60   # add a day in minutes if p is negative

# Convert p_minutes back to the "hh:mm" format
p_hours = p_minutes // 60
p_minutes = p_minutes % 60
print("{:02d}:{:02d}".format(p_hours, p_minutes))
