hdu 3750:guess game

#include <stdlib.h>
#include <string.h>
#include <math.
int ()
{
    
    system("Color F0");
    double ASL;
    int i,j,n,a;
    while (scanf("%d",&n)!=EOF)
    {
        ASL = 0;
        for ( i=1,j=1,a=1; a<=n; i++)
        {
                ASL += i*j*1.0/n;
                j *= 2;
                a = a+j;
        }
        ASL = ASL + i*(j-a+n)*1.0/n;
        printf("%.2fn",ASL);
    }
    return 0;
}