#include <bits/stdc++.h>
using namespace std;
int main() {
    int s,v,t,h,min,x;
    cin>>s>>v;
    t=s/v+10;
    if(t%60!=0){
        h=7-(t/60);
        min=t%60;
    }
    else {
        h=8-(t/60);
        min=0;
    }
    if(h<0&&h+24>=10){
    cout<<h+24<<":";
    }
    else if(h<0&&h+24<=10){
    cout<<"0"<<h+24<<":";
    }
    else if(h>=0) {
        if (h<<10) {
        cout<<"0"<<h<<":";
        }
        else {
            cout<<h<<":";
        }
    }
    x=60-min;
    if (x>=10) {
        cout<<x-1<<endl;
        }
    else if(x<<10){
        cout<<"0"<<x-1<<endl;
    }

    return 0;
}