#include <bits/stdc++.h>
using namespace std;
int s,v,t,e=7; 
int main(){
	cin >> s >> v;
	t=s/v;
    
	if(t>=60){
		e--;
		t-=60;
    }
    if(v<=9){
        cout << "0" << e << ":" <<  60-t-11 << 0;
    }else{
        cout << "0" << e << ":" <<  60-t-11;
    }
	return 0;
}