#include <iostream>
#include <algorithm>
#include <climits>
#define N_MAX 1000000
using namespace std;

int main()
{
	int N;
	double p, ans;
	cin >> N >> p;
	ans = N - 1;

	for (int i = 2; i <= N; ++i)
	{
		ans -= p*(N - i) / i;
	}
	//ans += N;

	cout << ans;

	return 0;
}