#include <bits/stdc++.h>
using namespace std;
ifstream fin("tribute.in");
ofstream fout("tribute.out");

int dist(vector<int>& a, int latura)
{
    sort(a.begin(), a.end());
    int st = 0, dr = a.size() - 1, s = 0;
    while(a[dr] - a[st] > latura)
        s += (a[dr--] - a[st++]) - latura;
    return s;
}

signed main()
{
    int n, L, l;
    fin >> n >> L >> l;
    vector<int> x(n), y(n);
    for(int i = 0; i < n; i++)
        fin >> x[i] >> y[i];
    fout << dist(x, L) + dist(y, l);

    return 0;
}