#include<bits/stdc++.h>
using namespace std;
int n,m,aa;
int main(){
	cin>>n>>m;
	int cc=ceil(n/m)+10;
	while(cc>=60){
		aa++;
		cc-=60;
	}
	aa=8-aa;
	cc=60-cc;
	if(aa<10){
		cout<<0<<aa-1<<":";
	} 
	if(cc<10){
		cout<<0<<cc-1;
	}
	if(aa>=10){
		cout<<aa-1<<":";
	}
	if(cc>=10){
		cout<<cc-1;
	}
	return 0;
}