#include<stdio.h>
int main()
{
    float s,v,t,o;
    int x,y;
    scanf("%f %f",&s,&v);
    if(v==0||s==0)
    	{printf("07:50");
    	    return 0;}
    o=1.0/6;
    t=8-s/v/60-o;
    if(t<0)
        t+=24;
    x=(int)t;
    y=(t-x)*60;
    printf("%02d:%02d",abs(x),abs(y));
    return 0;
}