#include <iostream>
#include <iomanip>

using namespace std;

int main()
{
	int n,m;
	double sum;
	while(1)
	{
		cin >> n;
		cin >> m;
		sum = 0;
		if(cin.eof())
		{
			break;
		}
		for(int i = m+1 ; i < n+1 ; i++)
		{
			sum += 1.0/i;
		}
		cout << fixed << setprecision(10) << sum << endl;
	}
	return 0;
}