#include <bits/stdc++.h>
using namespace std;
int n, c, d;
const int maxn = 3456789;
const long double PI = acos((long double)(-1.0));
const long double eps = 1e-18;
long double ang[maxn];
int main() {
  while (cin >> n >> c >> d) {
    for (int i = 0; i < (n); i++) {
      int r, w;
      scanf("%d%d", &r, &w);
      long double x = r - c;
      long double y = w - d;
      ang[i] = atan2(y, x);
    }
    sort(ang, ang + n);
    for (int i = 0; i < (n + 3); i++) ang[i + n] = ang[i] + 2 * PI;
    long long ans = 1LL * n * (n - 1) * (n - 2) / 6;
    int j = 0, lo = 0, hi = 0;
    for (int i = 0; i < (n); i++) {
      while (ang[j + 1] - ang[i] < PI + eps) ++j;
      while (ang[lo] - ang[i] < PI - eps) ++lo;
      while (ang[hi + 1] - ang[i] < PI + eps) ++hi;
      ans -= 1LL * (j - i) * (j - i - 1) / 2;
      ans += 1LL * (hi - lo) * (hi - lo + 1) / 2;
    }
    cout << ans << endl;
  }
  return 0;
}
