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

int sum(int m, int n, int now)
{
    if (n==now)
        return 3 * m + 1;
    else
        return sum(2 * m, n, now + 1) + sum(m + 1, n, now + 1) + sum(0, n, now + 1);
}

int main(void)
{
    int m, n;
    cin >> m >> n;
    double ans = sum(m, n, 1) / pow(3.0, n);
    printf("%.8f\n", ans);

    return 0;
}