// Source: https://usaco.guide/general/io #include <bits/stdc++.h> using namespace std; using ll = long long; using ld = long double; vector<pair<ld, ld>> points; ld L; ll n; bool ok(ld R) { ld cur = 0.0; for (auto [x, y] : points) { if (R < fabsl(y)) continue; ld dx = sqrt(R*R - y*y); ld l = max((ld)0.0, x - dx); ld r = min(L, x + dx); if (l > cur) return false; cur = max(cur, r); if (cur >= L) return true; } return cur >= L; } int main() { ios::sync_with_stdio(0); cin.tie(0); cin >> n >> L; points.resize(n); for (ll i = 0; i < n; i++) { cin >> points[i].first >> points[i].second; } ld lo = 0.0, hi = 2e9; for (int it = 0; it < 140; it++) { ld mid = (lo + hi) / 2; if (ok(mid)) hi = mid; else lo = mid; } cout << fixed << setprecision(6) << hi << "\n"; }