func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     ios_base::sync_with_stdio(0);     cin.tie(0);     long long n, d, a, b, x, y;     cin >> n >> d >> a >> b;     pair<long long, long long> arr[n];     for (int i = 0; i < n; i++) {       cin >> x >> y;       x *= a;       y *= b;       arr[i] = {x + y, i + 1};     }     sort(arr, arr + n);     vector<int> vec;     for (int i = 0; i < n; i++) {       if (d >= arr[i].first) {         d -= arr[i].first;         vec.push_back(arr[i].second);       } else         break;     }     cout << vec.size() << endl;     for (int i = 0; i < vec.size(); i++) cout << vec[i] <<    ;     return 0;   }   