#include <iostream>
int main()
{
int n = 0 ;
std::cin>>n;
double S= 0;
for(int i = 2; i<=n+1; ++i)
s = s+ 1/(double)i;
}
std::cout<<s;
return 0;
#include <iostream>
int main()
{
int n = 0 ;
std::cin>>n;
double S= 0;
for(int i = 2; i<=n+1; ++i)
{
s = s+ 1/(double)i;
}
std::cout<<s;
return 0;
}