#include<stdio.h>
main()
{
	double s=1,b=0;
	int n,i,j;
	scanf("%d",&n);
	for(i=1;i<=n;++i){
	for(j=1;j<=i;++j)
	{
		s=1.0/(s*i);}
		b=s+b;
	}
	printf("%.2lf",b);
	
	
}