#include <stdio.h>

int main()
{
    int s,v,t,o,p1,p2,c1,c2;
    double sum;
    scanf("%d %d",&s,&v);
    sum=s*1.0/v;
    t=s/v;
    o=t+1;
    if(sum==t)
    {
         p1=t/60;
         p2=t%60;
         c1=7-p1;
         c2=50-p2;
         if(c2<0)
         {
             c2=110-p2;
             p1--;
             if(c1<0)
                c1=31-p1;
            else if(p1<0)
                c1=6;
         }
         else if(c1<0)
            c1=31-p1;
    }
    else
    {
         p1=o/60;
         p2=o%60;
         c1=7-p1;
         c2=50-p2;
         if(c2<0)
         {
             c2=110-p2;
             p1--;
             if(c1<0)
                c1=31-p1;
            else if(p1<0)
                c1=6;
         }
         else if(c1<0)
            c1=31-p1;
    }
    printf("%02d:%02d",c1,c2);
    return 0;
}