#include <bits/stdc++.h>
using namespace std;
pair<int, int> arr[100001];
int main() {
  int n, d, a, b;
  cin >> n >> d >> a >> b;
  for (int i = 0; i < n; i++) {
    int c, d;
    cin >> c >> d;
    arr[i].first = c * a + d * b;
    arr[i].second = i + 1;
  }
  sort(arr, arr + n);
  long long counter = 0;
  int in = n;
  for (int i = 0; i < n; i++) {
    counter += arr[i].first;
    if (counter > d) {
      in = i;
      break;
    }
  }
  cout << in << endl;
  for (int i = 0; i < in; i++) {
    cout << arr[i].second << " ";
  }
  cout << endl;
  return 0;
}
