#include<bits/stdc++.h>
using namespace std;
int s,u,g,d,v,f;
int main(){
	cin>>s>>u;
	if(s%u!=0){
		f=s/u+1;
	}else{
		f=s/u;
	}
	d=480-10-f;
	if(d/60<10){
		g=d/60;
		v=d-g*60;
		if(v<10){
			cout<<"0"<<g<<":"<<"0"<<v;
		}else{
			cout<<"0"<<g<<":"<<v;
		}
	}else{
		g=d/60;
		v=d-g*60;
		if(v<10){
			cout<<g<<":"<<"0"<<v;
		}else{
			cout<<g<<":"<<v;
		}
	}
	return 0;
}