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,t=input().split(":"),input().split(":")
list1=[0,0,0,0]
if 0<=int(s[0])<=23 and 0<=int(t[0])<=23 and 0<=int(s[1])<=59 and 0<=int(t[1])<=59:
    if int(s[1])>=int(t[1]):
        a=str(int(s[1])-int(t[1]))
        if int(a)>9:
            list1[2],list1[3]=int(a[0]),int(a[1])
        else:
            list1[2],list1[3]=0,int(a[0])
    else:
        a=str(60+(int(s[1])-int(t[1])))
        if int(a)>9:
            list1[2],list1[3]=int(a[0]),int(a[1])
        else:
            list1[2],list1[3]=0,int(a[0])
        a=int(t[0])+1
        t[0]=a
    if int(s[0])>=int(t[0]):
        a=str(int(s[0])-int(t[0]))
        if int(a)>9:
            list1[0],list1[1]=int(a[0]),int(a[1])
        else:
            list1[0],list1[1]=0,int(a[0])
    else:
        a=str(24+(int(s[0])-int(t[0])))
        if int(a)>9:
            list1[0],list1[1]=int(a[0]),int(a[1])
        else:
            list1[0],list1[1]=0,int(a[0])

print(str(list1[0])+str(list1[1])+":"+str(list1[2])+str(list1[3]))