#include<bits/stdc++.h>

using namespace std;

using ll = long long;
using ld = long double;
using ull = unsigned long long;

using pii = pair<int, int>;
using pll = pair<ll, ll>;
using pld = pair<ld, ld>;

#define fi first
#define se second
#define pb push_back
#define pf push_front
#define mp make_pair
#define ins insert

#define sz(x) (int)(x.size());
#define all(x) x.begin(), x.end()
#define debug(...) " [" << #__VA_ARGS__ ": " << (__VA_ARGS__) << "] "

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

int d4x[4] = {1, 0, -1, 0}; int d4y[4] = {0, 1, 0, -1};
int d8x[8] = {0, 1, 1, 1, 0, -1, -1, -1};
int d8y[8] = {1, 1, 0, -1, -1, -1, 0, 1};

template<class X, class Y>
    bool minimize(X &x, const Y &y) {
        if (x > y)
        {
            x = y;
            return true;
        }
        return false;
    }
template<class X, class Y>
    bool maximize(X &x, const Y &y) {
        if (x < y)
        {
            x = y;
            return true;
        }
        return false;
    }

const int MOD = 1e9 + 7; //998244353

template<class X, class Y>
    void add(X &x, const Y &y) {
        x = (x + y);
        if(x >= MOD) x -= MOD;
    }

template<class X, class Y>
    void sub(X &x, const Y &y) {
        x = (x - y);
        if(x < 0) x += MOD;
    }

/* Author : Le Ngoc Bao Anh, 11A5, LQD High School for Gifted Student*/

const ll INF = 1e9;
const int N = 8005 + 10;

int par[N];
ll x[N], y[N];

struct Edges {
    int u, v, w;
} ed[N * N / 2];

int find_par(int u) {
    if(par[u] < 0) return u;
    par[u] = find_par(par[u]);
    return par[u];
}
void solve() {
    int n; ll h;
    cin >> n >> h;
    for(int i = 1; i <= n; i++) {
        cin >> x[i] >> y[i];
    }

    int cnt = 0;
    for(int i = 1; i <= n; i++) {
        ed[++cnt] = {0, i, (int)y[i]};
        ed[++cnt] = {n + 1, i, (int)(h - y[i])};
        for(int j = i + 1; j <= n; j++) {
            ed[++cnt] = {i, j, (int)sqrt((x[i] - x[j]) * (x[i] - x[j]) + (y[i] - y[j]) * (y[i] - y[j]))};
        }
    }

    for(int i = 0; i <= n + 1; i++) par[i] = -1;
    auto merge = [&](int u, int v) -> void {
        u = find_par(u), v = find_par(v);
        if(u == v) return;
        if(par[u] > par[v]) swap(u, v);
        par[u] += par[v];
        par[v] = u;
    };

    auto ok = [&](int dist) -> bool {
        for(int i = 0; i <= n + 1; i++) par[i] = -1;
        for(int i = 1; i <= cnt; i++) {
            if(ed[i].w <= dist) {
                merge(ed[i].u, ed[i].v);
                if(find_par(0) == find_par(n + 1)) return false;
            }
        }

        return true;
    };

    int L = 1, R = 1e9, ans = 1;
    while(L <= R) {
        int mid = (L + R) >> 1;
        if(ok(mid)) {
            ans = mid + 1;
            L = mid + 1;
        } else R = mid - 1;
    }

    cout << ans;
}

int main()
{
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    #ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
    #else
    //online
    #endif

    int tc = 1, ddd = 0;
    // cin >> tc;
    while(tc--) {
        //ddd++;
        //cout << "Case #" << ddd << ": ";
        solve();
    }
}