#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 result = 0;
	for (int i = n; i = n; i++)
	{
		double temp = a;
		for (int j = 1; j < i; j++)
		{
			temp *= (a + j);
		}
		result += 1 / temp;
	}
	cout << result;
	return 0;
	_getch();
}