#include <iostream>
#include <iomanip>
using namespace std;

int main()
{
    int s, v;
    cin >> s >> v;

    int time_garbge = 10;
    int time_road = s / v + time_garbge; // 计算结果是分钟,此处先用int,视测试情况更改
    int time_road_hour = time_road / 60;
    int time_road_min = time_road % 60 + 1;

    if (time_road_min == 1)
    {
        time_road_min = 0;
    }

    int time_togo_hour = 0;
    int time_togo_min = 0;

    // 如果消耗时间大于8，说明yyy在前一天已经出发了
    // 如果消耗时间小于8，说明yyy是当天出发
    if(time_road_hour >= 8)
    {
        time_togo_hour = 24 + 8 - time_road_hour - 1;
    }
    else
    {
        time_togo_hour = 8 - time_road_hour - 1;
    }

    time_togo_min = 60 - time_road_min;

    if (time_togo_min == 60)
    {
        time_togo_min = 0;
        time_togo_hour++;
    }

    cout << setw(2) << setfill('0') << time_togo_hour << ":" << setw(2) << setfill('0') << time_togo_min;

    return 0;
}