#include <bits/stdc++.h> using namespace std; int main(){ ios::sync_with_stdio(false); cin.tie(nullptr); int n; double l; cin>>n>>l; vector<pair<double, double> > points; double l_copy=0; double r_copy=2*l; for(int i=0; i<n; i++){ double a; double b; cin>>a>>b; points.push_back({a,b}); } double out=r_copy; while(l_copy<=r_copy-(1e-5)){ double mid=l_copy+(r_copy-l_copy)/2; double last_covered=0; for(int i=0; i<n; i++){ if(abs(points[i].second)<=mid){ double horizontal=sqrt(pow(mid,2)-pow(points[i].second, 2)); double l_curr=points[i].first-horizontal; double r_curr=points[i].first+horizontal; if(r_curr>=last_covered){ if(l_curr<=last_covered){ last_covered=r_curr; } } } } if(last_covered>=l){ out=min(out, mid); r_copy=mid-(1e-5); }else{ l_copy=mid+(1e-5); } } cout<<fixed<<setprecision(5)<<out<<"\n"; }