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