#include<stdio.h>
int main()
{
    int s,v,hour=1,min=0,hh;
    double t;
    scanf("%d%d",&s,&v);
    t=(double)s/v+10;
    while (t>=60)
    {
        t-=60;
        hour++;
    }
    min=(int)t;
    if (min<t)
        min++;
    if (8-hour<0)
    {
        hh=24+8-hour;
    }
    else hh=8-hour;
    printf("%02d:%d",hh,60-min);
}