#include<bits/stdc++.h>
using namespace std;
int main(){
	double a,b,r,f=480;
	int g=60,h=0,y=0;
	cin>>a>>b;
	r=a/b;
	f=f-(r+10);
	y=(int)f/g;
	h=(int)f%g;
	printf("%02d:%02d",y,h);
	return 0;
}