#include <stdio.h>
int main(void)
{
    int s, v;
    int output_hour, output_minute;
    scanf("%d %d", &s, &v);
    int time_minutes_whole;
    time_minutes_whole = s / v + 10;
    if (s % v != 0)
    {
        time_minutes_whole++;
    }
    int time_hours = 0;
    time_hours = time_minutes_whole / 60;
    int time_minutes_left = 0;
    time_minutes_left = time_minutes_whole % 60;
    if (time_minutes_left)
    {
        time_hours++;
    }
    if (time_hours < 8)
    {
        output_hour = 8 - time_hours;
    }
    else
    {
        output_hour = 24 - (time_hours - 8);
    }
    output_minute = 60 - time_minutes_left;
    if (output_hour < 10)
    {
        printf("0%d:%d", output_hour, output_minute);
    }
    else
    {
        printf("%d:%d", output_hour, output_minute);
    }
    return 0;
}