#include <iostream>
#include <stdio.h>

using namespace std;

int dx;
const int NMAX = 51000;
const int X = 51002;
int nrst[X], nrdr[X], vx[X], vy[X];
long long sumst[X], sumdr[X];

long long functie () {
    int i;
    long long minim;
    for (i = 1; i <= NMAX; i++)
        nrst[i] = nrst[i - 1] + vx[i - 1];
    for (i = 1; i <= NMAX; i++)
        sumst[i] = sumst[i - 1] + nrst[i];

    for (i = NMAX; i >= 0; i--)
        nrdr[i] = nrdr[i + 1] + vx[i + 1];
    for (i = NMAX; i >= 0; i--)
        sumdr[i] = sumdr[i + 1] + nrdr[i];

    minim = 50001;
    for (i = 0; i + dx - 1<= NMAX; i++)
        if (sumst[i] + sumdr[i + dx] < minim)
            minim = sumst[i] + sumdr[i + dx];
    return minim;
}


int main() {

    freopen ("tribute.in", "r", stdin);
    freopen ("tribute.out", "w", stdout);

    int n, px, dy, i, py;
    long long s1, s2;

    scanf ("%d%d%d", &n, &dx, &dy);

    for (i = 1; i <= n; i++) {
        scanf ("%d%d", &px, &py);
        vx[px]++;
        vy[py]++;
    }

    s1 = functie ();
    for (i = 0; i <= NMAX; i++) {
        nrst[i] = sumst[i] = sumdr[i] = nrdr[i] = vx[i] = 0;
        vx[i] = vy[i];
    }
    dx = dy;
    s2 = functie();
    printf ("%lld", s1 + s2);

    return 0;
}