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.
import sys;
s1=input();
s2=input();
a1=s1.split(":");
a2=s2.split(":");
t=[0,0];
if(a1[0]>=a2[0]):
    t[0]=int(a1[0])-int(a2[0]);
    if(a1[1]>=a2[1]):
        t[1]=int(a1[1])-int(a2[1]);
    else:
        t[0]=int(a1[0])-int(a2[0])-1;
        t[1]=int(a1[1])-int(a2[1])+60;
else:
    t[0]=int(a1[0])-int(a2[0])+24;
    if(a1[1]>=a2[1]):
        t[1]=int(a1[1])-int(a2[1]);
    else:
        t[0]=int(a1[0])-int(a2[0])-1;
        t[1]=int(a1[1])-int(a2[1])+60;
if((t[1]<10)&(t[0]<10)):
    print ("0%d:0%d" %(t[0],t[1]));
elif(t[0]<10):
    print ("0%d:%d"%(t[0],t[1]));
elif(t[1]<10):
    print ("%d:0%d"%(t[0],t[1]));

