#include <bits/stdc++.h>

using namespace std;

ifstream fin ("minim2.in");
ofstream fout ("minim2.out");

const int N_MAX = 1e5 + 5;

int n , m , v[N_MAX] , ans;
double a , b , q;

bool solve (int x){
    double ans = v[n] * a;
    x -= 1;
    for (int i=1; i<n; i++){
        ans += (double)b * v[i];
        x -= 1;
    }
    return (ans >= q && x >= 0);
}

int main(){
    ios_base::sync_with_stdio(false);
    fin >> n;
    for (int i=1; i<=n; i++){
        fin >> v[i];
    }
    fin >> a >> b >> q;
    sort(v + 1 , v + n + 1);

    int st = 1 , dr = 1e9;
    while (st <= dr){
        int mij = (st + dr) / 2;
        if (solve(mij)){
            ans = mij;
            dr = mij - 1;
        }
        else{
            st = mij + 1;
        }
    }
    fout << ans;
}