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.
hora1=input()
hora2=input()
hora1=hora1.split(":")
hora2=hora2.split(":")
Min=0
Hora=0
if(int(hora1[1])<int(hora2[1])):
    Hora-=1
    Min=60-(int(hora2[1])-int(hora1[1]))
if(int(hora1[1])>=int(hora2[1])):
    Min=int(hora1[1])-int(hora2[1])
if(int(hora1[0])<int(hora2[0])):
    Hora=Hora+24-(int(hora2[0])-int(hora1[0]))
if(int(hora1[0])>=int(hora2[0])):
    Hora=Hora+(int(hora1[0])-int(hora2[0]))
if(0<=Hora and Hora<=9):
    Hora="0"+str(Hora)
if(0<=Min and Min<=9):
    Min="0"+str(Min)
print(str(Hora)+":"+str(Min))
    
