//https://www.infoarena.ro/problema/tribute

//#pragma GCC optimize ("Ofast")
//#pragma GCC optimize ("fast-math")
//#pragma GCC optimize ("unroll-loops")
//#define _USE_MATH_DEFINES

#include <iostream>
#include <fstream>
//#include <vector>
//#include <cstring>
//#include <cmath>
//#include <bitset>
//#include <queue>
//#include <stack>
//#include <utility>
#include <algorithm>
//#include <string>
//#include <map>
//#include <unordered_map>
//#include <set>
//#include <unordered_set>
//#include <cstdint>
//#include <climits>
//#include <iomanip>
//#include <cstdio>
//#include <tuple>

using namespace std;

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

const int NRMAX = 50000;

int rezolvare(int v[], int n, int d)
{
	sort(v + 1, v + n + 1);

	/*for (int i = 1; i <= n; ++i)
		cout << v[i] << " ";
	cout << "\n";*/

	int i = 1, j = n, rez = 0;
	int dist = v[j] - v[i] - d;
	while (dist >= 1)
	{
		rez += dist;
		++i;
		--j;
		dist = v[j] - v[i] - d;
	}

	return  rez;
}

int main()
{
	//ios_base::sync_with_stdio(false);
	//cin.tie(NULL);

	int n, dx, dy, i, x[NRMAX + 5], y[NRMAX + 5];

	fin >> n >> dx >> dy;
	for (i = 1; i <= n; ++i)
	{
		fin >> x[i] >> y[i];
	}

	fout << rezolvare(x, n, dx) + rezolvare(y, n, dy);

	return 0;
}