#include <iostream>

using namespace std;

#define x first
#define y second

int const NMAX = 1e5;
int n, k;
pair<int, int> p[1 + NMAX];

long long dist(int i, int j) {
    return 1LL * (p[i].x - p[j].x) * (p[i].x - p[j].x) + 1LL * (p[i].y - p[j].y) * (p[i].y - p[j].y);
}

long long binarysearch(long long from, long long to, double val) {
    if (from < to) {
        long long guess = (from + to)/2;
        if (1.0 * guess * guess < val) {
        	return binarysearch(guess+1, to, val);
        } else {
        	return binarysearch(from, guess, val);
        }
    }
    return from;
}

int main() {
    cin >> n >> k;
    for (int i = 1; i <= n; i++) {
        cin >> p[i].x >> p[i].y;
    }
    int l = 1, r = 1;
    long long max_dist = 0;
    int counter = 0;
    while (l <= n) {
        if ((r == n && dist(l, 1) > dist(l, r)) || (r != n && dist(l, r+1) > dist(l, r))) {
            r++;
            if (r > n) {
                r = 1;
            }
        } else {
            long long new_dist = dist(l, r);
            if (new_dist == max_dist) {
                counter++;
            } else if (new_dist > max_dist) {
                counter = 1;
                max_dist = new_dist;
            }
            l++;
        }
    }
    counter /= 2;
    long long sqr = binarysearch(1, max_dist, max_dist);
    if (sqr * sqr == max_dist) {
        long long ans = k / (2 * sqr);
        if (2 * ans * sqr == k && ans > counter || 2 * ans * sqr != k) {
            ans++;
        }
        cout << ans << "\n";
    } else {
        long long ans = binarysearch(1, 1e18, (1.0 * k * k) / (4.0 * max_dist));
        cout << ans << "\n";
    }
    //cout << k << " " << sqr << "\n";
}