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.
HH1=input()
HH2=input()
HH=HH1.split(":")
HH3=HH2.split(":")
HH5=int(HH[0])
HH6=int(HH[1])
HH7=int(HH3[0])
HH8=int(HH3[1])
str1=""
def MM(HH,HH3,str1):
    aux=str(HH6-HH8)
    if(len(aux)==2):
        str1+=aux
    else:
        str1+="0"+aux
    print(str1)
    return str1
def HH11(HH,HH3,str1):
    if(HH5==HH7):
        str1+="00"+":"
        str1+=MM(HH,HH3,str1)
    else:
        if(HH5>HH7):
            aux=str(HH5-HH7)
            if(len(aux)==2):
                str1+=aux+":"
                str1+=MM(HH,HH3,str1)
            else:
                str1+="0"+aux+":"
                str1+=MM(HH,HH3,str1)
        else:
            print("23:00")
HH11(HH,HH3,str1)