#include <bits/stdc++.h>
#define int long long
#define TASKNAME "garland"
using namespace std;
typedef long double ld;

const int N = 1e5 + 7, ITER = 100;

ld h[N];
ld ans = 0;

bool can(int n, ld h1, ld x) {
    ld prev = h1, cur = x;
    bool res = (cur > 0);
    for(int i = 2; i < n; i ++)
    {
        ld next = cur * 2.0 - prev + 2.0;
        if(!(next > 0))
        {
            res = 0;
            break;
        }
        prev = cur, cur = next;
    }
    if(res)
        ans = cur;
    return res;
}

int32_t main() {
    srand(time(NULL));
    freopen(TASKNAME".in", "r", stdin);
    freopen(TASKNAME".out", "w", stdout);
    int n;ld h1;
    cin >> n >> h1;
    ld l = 0, r = h1;
    int it = 0;
    while(it < ITER)
    {
        it ++;
        ld m = (l + r) / 2;
        if(can(n, h1, m))
            r = m;
        else
            l = m;
    }
    cout << fixed << ans << endl;
}