#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <atcoder/modint>
using namespace std;
using i32 = int;
using u32 = unsigned int;
using i64 = long long;
using u64 = unsigned long long;
#define rep(i,n) for(int i=0; i<(int)(n); i++)
const i64 INF = 1001001001001001001;

using Modint = atcoder::static_modint<998244353>;

int main(){
    int N; cin >> N;
    int H; cin >> H;
    double h = (double)H / 2;
    vector<double> X(N), Y(N);
    rep(i,N) cin >> X[i] >> Y[i];
    vector<int> I(N); rep(i,N) I[i] = i;
    rep(i,N) Y[i] -= h;
    sort(I.begin(), I.end(), [&](int l, int r) -> bool {
        return X[l] * Y[r] - X[r] * Y[l] > 0;
    });
    rep(t,2){
        vector<double> F(N);
        rep(i,N) F[i] = X[I[i]];
        swap(X, F);
        swap(X, Y);
    }
    auto XI = X;
    XI.push_back(0.0);
    sort(XI.begin(), XI.end());
    double ans = 1e100;
    auto xxx = [](double xx, double xy, double yy){
        return (xx == 0.0) ? 0.0 : (yy - xy*xy/xx);
    };
    for(double xc : XI){
        vector<double> XX0(N+1), XY0(N+1), YY0(N+1);
        vector<double> XX1(N+1), XY1(N+1), YY1(N+1);
        vector<double> f(N+1);
        rep(t,2){
            vector<double> X0, X1, Y0, Y1;
            rep(i,N){
                if(X[i] <= xc){
                    X0.push_back(X[i]);
                    X1.push_back(0);
                    Y0.push_back(Y[i]+h);
                    Y1.push_back(0);
                } else {
                    X0.push_back(0);
                    X1.push_back(X[i]);
                    Y0.push_back(0);
                    Y1.push_back(Y[i]+h);
                }
            }
            if(t){ swap(X0,X1); swap(Y0,Y1); }
            
            rep(i,N) XX0[i+1] = XX0[i] + X0[i] * X0[i];
            for(int i=N-1; i>=0; i--) f[i] = f[i+1] + X1[i] * X1[i];
            rep(i,N+1) XX0[i] += f[i];

            rep(i,N) XY0[i+1] = XY0[i] + X0[i] * Y0[i];
            for(int i=N-1; i>=0; i--) f[i] = f[i+1] + X1[i] * Y1[i];
            rep(i,N+1) XY0[i] += f[i];

            rep(i,N) YY0[i+1] = YY0[i] + Y0[i] * Y0[i];
            for(int i=N-1; i>=0; i--) f[i] = f[i+1] + Y1[i] * Y1[i];
            rep(i,N+1) YY0[i] += f[i];

            swap(XX0,XX1); swap(XY0,XY1); swap(YY0,YY1);
            h = -h;
        }
        for(int s=0; s<=N; s++){
            double c0 = xxx(XX0[s],XY0[s],YY0[s]);
            double c1 = xxx(XX1[s],XY1[s],YY1[s]);
            ans = min(ans, c0 + c1);
        }
    }
    cout.precision(10);
    fixed(cout);
    cout << ans << endl;
    return 0;
}

struct ios_do_not_sync{
    ios_do_not_sync(){
        ios::sync_with_stdio(false);
        cin.tie(nullptr);
    }
} ios_do_not_sync_instance;