#include<iostream>
#include<cmath>
using namespace std;
int main(){
    int a,b;
    int c;
    double d,e;
    cin>>a>>b;
    c=int(a/b+0.999999999)+10;
    d=int((8-ceil(c/60.0)));
    if(d<0) d+=24;
    e=60-(c+1)%60;
    if(d<10){
        if(e<10) cout<<"0"<<d<<":"<<"0"<<e;
        else cout<<"0"<<d<<":"<<e;
    }
    else{
        if(e<10) cout<<d<<":"<<"0"<<e;
        else cout<<d<<":"<<e;
    }
}