#include<iostream>
using namespace std;
int main(){
	int s,a=480,b,i,u;
	cin>>s>>u;
	if(s%u==0){
		 i=s/u+10;
	}else{
		 i=s/u+1+10;
	}
    b=a-i;
	int s1=b%60;
	int s2=b/60;
	int s3=60-s1;
	if(s2<10){
		cout<<"0"<<s2;
	}
	if(s1<10){
		cout<<"0"<<s1;
	}
	cout<<s2<<":"<<s1;
	
	return 0;
}