#include <bits/stdc++.h>
using namespace std;
#define int long long
mt19937_64 RNG(chrono::steady_clock::now().time_since_epoch().count());
const int N = 1e6 + 5;
vector<pair<long double, long double> > coordinates(N);
int n, l;
bool Check(long double value)
{
// sqrt[(c[i].x - x) ^ 2 + (c[i].y - 0) ^ 2] = value
// (c[i].x - x) ^ 2 + c[i].y ^ 2 = value * value
// c[i].x - x = sqrt[(value * value) - c[i].y ^ 2]
// - x = sqrt[(value * value) - c[i].y ^ 2] - c[i].x
// x = c[i].x - sqrt[(value * value) - c[i].y ^ 2]
long double maxLeft = 0;
for(int i = 1; i <= n; i++)
{
long double cur_left = 0.0, cur_right = 0.0;
cur_left = coordinates[i].first - sqrt((value * value) - (coordinates[i].second * coordinates[i].second));
cur_right = coordinates[i].first + sqrt((value * value) - (coordinates[i].second * coordinates[i].second));
if(cur_left <= maxLeft)
{
maxLeft = max(maxLeft, cur_right);
}
}
return (maxLeft >= l);
}
void Solve()
{
cin >> n >> l;
for(int i = 1; i <= n; i++)
{
cin >> coordinates[i].first >> coordinates[i].second;
}
long double left = 0, right = 1e9;
long double ans = right + 1;
while(right - left >= 0.0001)
{
// cout << "left = " << left << ", right = " << right << "\n";
long double mid = (left + right) / 2;
if(Check(mid))
{
right = mid;
ans = mid;
}
else
{
left = mid;
}
}
cout << fixed << setprecision(8) << ans << "\n";
}
int32_t main()
{
auto begin = std::chrono::high_resolution_clock::now();
ios_base::sync_with_stdio(0);
cin.tie(0);
int t = 1;
// cin >> t;
for(int i = 1; i <= t; i++)
{
//cout << "Case #" << i << ": ";
Solve();
}
auto end = std::chrono::high_resolution_clock::now();
auto elapsed = std::chrono::duration_cast<std::chrono::nanoseconds>(end - begin);
cerr << "Time measured: " << elapsed.count() * 1e-9 << " seconds.\n";
return 0;
}
