#include <iostream>
#include <fstream>
#include <algorithm>

using namespace std;

ifstream fin ("tribute.in");
ofstream fout ("tribute.out");

int n, dx, dy;
int a[50005], b[50005];
int formula (int v[], int d) {
    int i = 1, j = n, distanta_temp = 0;
    while (i <= j) {
        if (v[j] - v[i] - dx > 0)
            distanta_temp += v[j] - v[i] - dx;
        i++;
        j--;
    }
    return distanta_temp;
}

int main() {
    fin >> n >> dx >> dy;
    for (int i = 1; i <= n; i++)
        fin >> a[i] >> b[i];
    sort (a + 1, a + 1 + n);
    sort (b + 1, b + 1 + n);
    fout << formula (a, dx) + formula (b, dx) << "\n";
    return 0;
}