#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <conio.h>
#include <math.h>
#include <float.h>
#include <locale.h>

double FTWTRYHARD(const double a, const int n) {
    double temp = a;
    double result = 1.0 / a;
    for (int i = 1; i <= n; i += 1) {
        temp *= (a + i);
        result += 1.0 / temp;
    }
    return result;
}

int main() {
    int n;
    double a;
    scanf("%lf%i", &a, &n);
    printf("%.4f\n", FTWTRYHARD(a, n));
    _getch();
}