#include<stdio.h>
int main()
{
    int s,v;
    scanf("%d%d",&s,&v);
    int st=(24+8)*60;
    int t;
    
    if(s/v!=0)
    {
        t=11+s/v;
    }
    else
    {
        t=s/v+10;
    }
    
    int gt=st-t;
    
    if(t<8*60)
    {
        gt-=24*60;
    }
    
    int h=gt/60;
    int m=gt%60;
    
    printf("%02d:%02d",h,m);
    return 0;
}