#include <stdio.h>
#include <iostream>
#include <math.h>
#include <conio.h>
using namespace std;

int main()
{
	int n;
	double a;
	cin >> a;
	cin >> n;
	double temp = a;
	double result = 0;
	for (int i = 0; i < n + 1; i++)
	{
		temp *= a + i;
		result += 1 / temp;
	}
	cout << result;
	cin >> a;
	return 0;
}