hdu-2156-分数矩阵

#include<stdio.h>

int main()

{
int n;
while(scanf("%d",&n)&&n)
{
int i;
   double sum=0.0,s=0.0;
for(i=1;i<=n;i++)
{
s=s+1.0/i;
sum+=s;
}
sum=sum*2-n;
printf("%.2lf\n",sum);
}
return 0;

}