#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
using namespace std;





int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);

    vector <int> a,b(2001);
    int n, k,q(-1),min(1e9);
    cin >> n;
    a.resize(n);

    for (int i(0); i < n; i++)
    {
        cin >> a[i];
        b[a[i]] = 1;
    }
    cin >> k;
    b.resize(k+1);
    sort(a.begin(), a.end());
    for (int i(1); i <= k; i++)
    {
        if (b[i] != 1){
            for (int j(0); j < n; j++)
            if (a[j] < i)
                q = j;
            for (int j(0); j <= q; j++)
            if (b[i - a[j]] < min)
                min = b[i - a[j]];

            b[i] = min + 1;

            min = 1e9;

        }
    }
    if (b[k] == 1e9+1)
        cout << -1;
    else
    cout << b[k];

    return 0;
}


/*


*/