#include <vector> 
#include <list> 
#include <map> 
#include <set> 
#include <deque> 
#include <queue> 
#include <stack> 
#include <bitset> 
#include <algorithm> 
#include <functional> 
#include <numeric> 
#include <utility> 
#include <sstream> 
#include <iostream> 
#include <iomanip> 
#include <cstdio> 
#include <cmath> 
#include <cstdlib> 
#include <cctype> 
#include <string> 
#include <cstring> 
#include <ctime> 

using namespace std;

#define _int64 long long

double c=0.57721;
double ans[1000000];

int main()
{
  int i,n;
  double tmp;
  ans[0]=0;
  for (i=1;i<1000000;i++)
    ans[i]=ans[i-1]+1.0/i;
  while (scanf("%d",&n)!=EOF)
  {
    if (n<1000000)
    {
      printf("%.4lf\n",ans[n]);
      /*
      tmp=log(n)+c;
      printf("%.4lf\n",tmp);
      */
    }
    else
    {
      tmp=log(n)+c;
      printf("%.4lf\n",tmp);
    }
  }
}