#include <stdio.h>
#include <iostream>
using namespace std;
using namespace std;
using namespace std;
int main()
{
    int distance;
    int speed;
    int minites;
    int hours;
    int x;
    cin >> distance >> speed;
    if (distance % speed != 0) {
        x = (distance / speed) + 1;
    }
    else { x = distance / speed; }
    if (x > 470) {
        hours = 31 - (x / 60);
        minites = x % 60;
        if (minites > 50) {
            hours -= 1;
            minites = 110 - minites;
        }
        else {
            minites = 50 - minites;
        }

     }
    else {
        hours = 7 - (x / 60);
        minites = x % 60;
        if (minites > 50) {
            hours -= 1;
            minites = 110 - minites;
        }
        else {
            minites = 50 - minites;
        }
               }
    
    if (hours> 10) {
        if (minites > 10) {
            cout << hours << ":" << minites << endl;
        }
        else {
            cout << hours << ":0" << minites << endl;
        }
}
else {
        if (minites > 10) {
            cout <<"0"<< hours << ":" << minites << endl;
        }
        else {
            cout << "0" << hours << ":" << minites << endl;
        }
}
    }