#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define ll long long
#define db double
#define pii pair<int, int>
#define pll pair<ll, ll>
#define fi first
#define se second
#define pb push_back
#define all(x) begin(x), end(x)
#define allr(x) rbegin(x), rend(x)
#define szx(x) ((int)(x).size())
#define FOR(i, a, b) for (int i = a, _b = (b); i <= _b; ++i)
#define ROF(i, a, b) for (int i = a, _b = (b); i >= _b; --i)
#define REP(i, n) for (int i = 0, _n = (n); i < _n; ++i)
#define endl '\n'
#define inf 1000000007
#define mod 1000000007
// #define mod 998244353
using namespace std;
using namespace __gnu_pbds;
void setIO() {
ios::sync_with_stdio(0);
cin.tie(0);
}
void openFile(string filename = "") {
if (!filename.empty())
if (ifstream(filename + ".in")) {
freopen((filename + ".in").c_str(), "r", stdin);
freopen((filename + ".out").c_str(), "w", stdout);
}
}
ll binpow(ll a, ll b, int m = mod) {
ll res = 1;
a %= m;
while (b) {
if (b & 1) res = (a * res) % m;
a = (a * a) % m;
b >>= 1;
}
return res;
}
const int FMAX = 2e5 + 5;
ll fact[FMAX], invf[FMAX];
void process() {
fact[1] = fact[0] = invf[1] = invf[0] = 1;
FOR(i, 2, FMAX - 1) fact[i] = (fact[i - 1] * i) % mod;
invf[FMAX - 1] = binpow(fact[FMAX - 1], mod - 2, mod);
ROF(i, FMAX - 1, 1) invf[i - 1] = invf[i] * i % mod;
}
ll comb(int a, int b) {
b = min(b, a - b);
if (a < 0 || b < 0) return 0;
return fact[a] * (invf[b] * invf[a - b] % mod) % mod;
}
const int PMAX = 1e6 + 5;
bool prime[PMAX + 1];
void sieve() {
fill(prime, prime + PMAX + 1, 1);
prime[0] = prime[1] = 0;
for (int i = 2; i * i <= PMAX; i++) {
if (prime[i] == 0) continue;
prime[i] = 1;
for (ll j = i * i; j <= PMAX; j += i) prime[j] = 0;
}
}
struct DSU {
vector<int> comp;
ll ans = 0;
DSU(int n) { comp.assign(n + 5, -1); }
int find(int v) { return comp[v] < 0 ? v : comp[v] = find(comp[v]); }
void unite(int u, int v) {
u = find(u), v = find(v);
if (u == v) return;
if (comp[u] > comp[v]) swap(u, v);
comp[u] += comp[v];
comp[v] = u;
}
int getsz(int v) { return -comp[find(v)]; }
bool same(int u, int v) { return find(u) == find(v); }
};
struct Point {
db x, y;
Point(db x, db y) : x(x), y(y) {}
Point() {};
};
struct Vector {
ll x, y;
Vector(Point A, Point B) {
x = A.x - B.x;
y = A.y - B.y;
}
Vector(ll x, ll y) : x(x), y(y) {};
Vector PerpenVec() { return Vector(y, -x); }
};
struct Line {
ll a, b;
db c;
Line(Vector v, Point A) {
Vector PerpenVec = v.PerpenVec();
a = PerpenVec.x;
b = PerpenVec.y;
c = -(a * A.x + b * A.y);
}
};
Line bisectorLine(Point A, Point B) {
Point midPoint = Point((A.x + B.x) / 2, (A.y + B.y) / 2);
Vector v = Vector(A, B).PerpenVec();
return Line(v, midPoint);
}
Point intersec(Line A, Line B) {
ll delta = A.b * B.a - A.a * B.b;
if (delta == 0) return Point(-inf, -inf);
return Point(1.0 * (A.c * B.b - A.b * B.c) / delta, -1.0 * (A.c * B.a - A.a * B.c) / delta);
}
db distance(Point A, Point B) {
return sqrt((A.x - B.x) * (A.x - B.x) + (A.y - B.y) * (A.y - B.y));
}
const int MAX = 1e6 + 5;
int n, l;
Point stations[MAX];
Line Ox = Line(Vector(1, 0), Point(0, 0));
map<int, int> mp;
void solve() {
stack<Point> st;
n = szx(mp);
int cnt = 0;
for (pii p : mp) stations[cnt].x = p.fi, stations[cnt].y = p.se, cnt++;
REP(i, n) {
while (szx(st) >= 2) {
Point B = st.top();
st.pop();
Point A = st.top();
Line b1 = bisectorLine(A, B), b2 = bisectorLine(B, stations[i]);
if (intersec(b1, Ox).x < intersec(b2, Ox).x) {
st.push(B);
break;
}
}
st.push(stations[i]);
}
db ans = -1e18;
db mn1 = 1e18, mn2 = 1e18;
REP(i, n)
mn1 = min(mn1, distance(Point(0, 0), stations[i])),
mn2 = min(mn2, distance(Point(l, 0), stations[i]));
ans = max(mn1, mn2);
while (szx(st) >= 2) {
Point A = st.top();
st.pop();
Point B = st.top();
Point C = intersec(bisectorLine(A, B), Ox);
db d = distance(C, A);
if (C.x >= 0 && C.x <= l) ans = max(ans, d);
}
cout << ans;
}
void input() {
cin >> n >> l;
REP(i, n) {
int x, y;
cin >> x >> y;
if (!mp.count(x) || abs(mp[x]) > abs(y)) mp[x] = y;
}
}
void preprocess() {}
int main() {
setIO();
openFile("main");
int t = 1;
// cin >> t;
preprocess();
while (t--) {
input();
solve();
}
}
