include <bits/stdc++.h>

using namespace std;

int32_t main()
{
    int n, x;
    cin >> n >> x;

    double ans = 0;
    double p = 1;
    double f = 1;

    for (int i = 1; i < n + 2; ++i)
    {
        ans += p / f;
        p *= x;
        f *= i;
    }

    cout << fixed << setprecision(6) << ans;

    return 0;
}