#include <stdio.h>
#include <time.h>
clock_t start,stop;
double duration;
int main()
{int i,b,n,center,left,right,a[10000];
   scanf("%d",&n);
   start=clock();
   for(b=0;b<10000;b++)
   {
	   for(i=0;i<n;i++)
	   a[i]=i;
   left=0;
   right=n-1;
   for(i=0;i<n/2;i++)
	{ if(left!=right)
	   {
	   center=(left+right)/2;
	   if(n>a[center])
	       left=center;
       if(n<a[center])
		   right=center;
	   }
   }}
	stop=clock();
	duration=((double)(stop-start))/CLK_TCK;
	printf("%lf",duration);
}