#include<bits/stdc++.h>
using namespace std;
int main()
{
    int s=0,v=0,cost=0,h=0,m=0;
    scanf("%d%d",&s,&v);
    cost=ceil(s*1.0/v)+10;
    if(cost>=24*60)
    cost%=24*60;
    h=7-cost/60;
    m=60-cost%60;
    printf("%02d:%02d",h,m);
    return 0;
}