#include<iostream>
using namespace std;
int s,v;
int main(){
	cin>>s>>v;
	int m;
	int dh;
	if(s%v==0){
		m = s/v + 10; 
	}else{
		m = s/v + 10 + 1; 
	}
	if(m%60==0){
		dh = m/60;
	}else{
		dh = m/60 + 1;
	}
	int h = 8;
	if(h-dh>=0){
		h -= dh;
	}else{
		h = 24 - dh + 8;
	}
	int n = (-1) * (m - dh * 60);
	if(h>10){
		if(n>10){
			cout<<h<<":"<<n;
		}else{
			cout<<h<<":0"<<n;
		}
	}else{
		if(n>10){
			cout<<"0"<<h<<":"<<n;
		}else{
			cout<<"0"<<h<<":0"<<n;
		}
	}
}