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.
def PRINT(yy):
    a=yy//3600
    if a == 0:print('00:',end="")
    elif a > 10:print(str(a)+':',end="")
    else:print('0'+str(a)+':')
    yy%=3600
    a = yy//60
    if a == 0:print('00')
    elif a > 10:print(str(a))
    else:print('0'+str(a))
class MyApp():
    
    def __init__(self,s,t):
        self.s = s
        self.t = t
    
    def build(self):
        S = self.s.split(':')
        T = self.t.split(':')
        S = (int(S[0])*3600)+(int(S[1])*60)
        T = (int(T[0])*3600)+(int(T[1])*60)
        self.yy = S-T
        #print(S,T,self.yy)
        
        if self.yy > 0:
            PRINT(self.yy)

        elif self.yy < 0:
            self.yy = 86400 - abs(self.yy)
            PRINT(self.yy)
        else:
            print('00:00')
root = MyApp(input(),input())
root.build()
