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.
from collections import Counter
import statistics
import math
ints = lambda: list(map(int, input().split()))
st = lambda x: statistics.mode(x)
cnr = lambda x: Counter(x)
tw = lambda n: (n&(n-1)==0) and n!=0

h1,m1=map(int, input().split(":"))
h2,m2=map(int, input().split(":"))

h3,m3=h1-h2,m1-m2
if m3<0: m3=60+m3; h3-=1
if h3<0: h3=24+h3
if len(str(h3))==1: h3="0"+str(h3)
if len(str(m3))==1: m3="0"+str(m3)
print(h3,m3,sep=":")
