#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n, d, a, b;
  cin >> n >> d >> a >> b;
  vector<pair<long long, int> > v(n);
  for (int i = 0; i < n; i++) {
    long long x, y;
    cin >> x >> y;
    v[i].first = x * a + y * b;
    v[i].second = i + 1;
  }
  sort(v.begin(), v.end());
  int ans = 0, sum = 0, pos = 0;
  for (int i = 0; i < n; i++) {
    if (sum + v[i].first <= d) {
      sum += v[i].first;
      ans++;
      pos = i;
    }
  }
  cout << ans << endl;
  if (ans)
    for (int i = 0; i <= pos; i++) cout << v[i].second << ' ';
  return 0;
}
