#include<bits/stdc++.h>
using namespace std;
int a,b,k,l=10,m;
int main()
{
	cin>>a>>b;
	while(k<a){
		k+=b;
		l++;
	}	
	m=l/60;
	l%=60;
	if(l!=0){
		m++;
	}
	m=8-m;
	if(m<0){
		m=-m;
		m=24-m;
	}
	if(m>9){
		cout<<m;
	}else{
		cout<<"0"<<m;
	}
	if(l>9){
		cout<<":"<<60-l;
	}else{
		cout<<":"<<"0"<<60-l;
	}
} 

60分 3,4,5,7测试点没过 求助