#include <bits/stdc++.h>
using namespace std;
int n,m,k;
int main() {
	scanf("%d%d",&n,&m);
	if ( n%m==0 ) 
		k=n/m+10;
	else 
		k=n/m+10+1;
	int time;
	if ( k>480 ) 
		time=1440-k;
	else 
		time=480-k;
	int x=time/60;
	int y=time%60;
	if ( x/10==0 ) 
		printf("0%d",x);
	else 
		printf("%d",x);
	if ( y/10==0 ) 
		printf(":0%d",y);
	else 
		printf(":%d",y);	
	return 0;
}