#include <fstream>
#include <vector>
#include <algorithm>
using namespace std;

int suma_distante(vector <int> &v, int lung)
{
    int suma=0, st=0, dr=(int)v.size() - 1;
    while(st < dr && v[dr] - v[st] > lung)
    {
        suma += v[dr] - v[st] - lung;
        st++;
        dr--;
    }
    return suma;
}
int main()
{
    ifstream in("tribute.in");
    ofstream out("tribute.out");
    int n, dx, dy;
    in >> n >> dx >> dy;
    vector <int> x(n), y(n);
    for(int i=0; i<n; i++)
    {
        in >> x[i] >> y[i];
    }
    in.close();
    out << (long long)suma_distante(x,dx) + suma_distante(y,dy) << "\n";
    out.close();
    return 0;
}