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][1])>=int(t[1][1]):
        list1[3]=str(int(s[1][1])-int(t[1][1]))
        a=int(t[1][0])
    else:
        list1[3]=str((10+int(s[1][1]))-int(t[1][1]))
        a=int(t[1][0])
        a+=1
    if int(s[1][0])>=a:
        list1[2]=str(int(s[1][0])-a)
        b=int(t[0][1])
    else:
        list1[2]=str((6+int(s[1][0]))-a)
        b=int(t[0][1])
        b+=1
    if int(s[0][1])>=b:
        list1[1]=str(int(s[0][1])-b)
        c=int(t[0][0])
    else:
        list1[1]=str((4+int(s[0][1]))-b)
        c=int(t[0][0])
        c+=1
    if int(s[0][0])>=c:
        list1[0]=str(int(s[0][0])-c)
    else:
        list1[0]=str((3+int(s[0][0]))-c)
print(list1[0]+list1[1]+":"+list1[2]+list1[3])
    