#include<iostream>
using namespace std;
int main()
{
int n=1,m;
float sum=0;
cin>>m;
while(n<=m)
{
sum=sum+1.0/n;
n++;
}
cout<<sum<<endl;
return 0;
}
#include<iostream>
using namespace std;
int main()
{
int n=1,m;
float sum=0;
cin>>m;
while(n<=m)
{
sum=sum+1.0/n;
n++;
}
cout<<sum<<endl;
return 0;
}