#include <bits/stdc++.h>
using namespace std;
const long long INF = (long long)LLONG_MAX;
int dx[4] = {0, -1, 0, 1};
int dy[4] = {1, 0, -1, 0};
int dx8[9] = {1, 0, -1, 0, 1, -1, -1, 1, 0};
int dy8[9] = {0, 1, 0, -1, 1, -1, 1, -1, 0};
long long ipow(long long base, long long exp) {
  long long result = 1;
  while (exp) {
    if (exp & 1) result *= base;
    exp >>= 1;
    base *= base;
  }
  return result;
}
string tos(long long n) {
  stringstream ss;
  string ans;
  ss << n;
  ss >> ans;
  return ans;
}
long long toll(string n) { return atoll(n.c_str()); }
double dist(double x1, double y1, double x2, double y2) {
  return sqrt(((x1 - x2) * (x1 - x2)) + ((y1 - y2) * (y1 - y2)));
}
int doubleCompare(double x, double y) {
  if (fabs(x - y) <= 1e-5) return 0;
  if (x < y) return -1;
  return 1;
}
int main() {
  int n, mem, a, b, x, y;
  cin >> n >> mem >> a >> b;
  pair<long long, int> arr[n];
  for (int i = 0; i < n; i++) {
    cin >> x >> y;
    arr[i] = make_pair((a * x) + (b * y), i + 1);
  }
  sort(arr, arr + n);
  vector<int> ans;
  for (int i = 0; i < n; i++) {
    if (mem < arr[i].first) {
      break;
    } else {
      mem -= arr[i].first;
      ans.push_back(arr[i].second);
    }
  }
  cout << ans.size() << endl;
  for (int i = 0; i < ans.size(); cout << ans[i++] << " ")
    ;
}
