#include<bits/stdc++.h>
using namespace std;
int main(){
    int a,b,f;
    cin>>a>>b;
    if(a%b==0){
    	f=a/b;
	}else{
		f=a/b+1;
	}
	if(f>=24*60){
		f=f-24*60;
	}	
    int j=8*60-f-10;
	int j1=floor(j/60);
	int j2=j%60;
	if(j1<10){
		cout<<"0"<<j1<<":";
		if(j2<10){
			cout<<"0"<<j2;
			return 0;
		}else{
			cout<<j2;
			return 0;
		}
	}else{
		cout<<j1<<":";
		if(j2<10){
			cout<<"0"<<j2;
			return 0;
		}else{
			cout<<j2;
			return 0;
		}
	}
    cout<<j1<<":"<<j2;
    return 0;
}