#include <bits/stdc++.h>
using namespace std;
const long double EPS = 1e-2;
int n;
pair<bool, long double> check(long double m, long double prev) {
    long double tec = m;
    bool ok = (tec > 0);
    for(int i = 2; i < n; ++i) {
        long double c = 2.0 + 2.0 * tec - prev;
        if(!(c > 0)) {
            return {false, tec};
        }
        prev = tec;
        tec = c;
    }
    return {ok, tec};
}

int32_t main()
{

    //freopen("garland.in", "r", stdin);
    //freopen("garland.out", "w", stdout);

    long double x;
    cin >> n >> x;
    long double l = 0, r = x, ans = 0;
    for (int i = 0; i < 50; ++i) {
        long double m = (l + r) / 2.0;
        auto checked = check(m , x);
        if(checked.first) {
            r = m;
            ans = checked.second;
        }
        else
            l = m;
    }
    cout.precision(10);
    cout << fixed << ans << endl;
}