#include <bits/stdc++.h>
#define lli long long int
using namespace std;

struct greaters {
    bool operator() (const long&a, const long&b) const {
        return a > b;
    }
};

int main (int argc, char *argv[]) {

    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    vector<int> v;
    lli ans = 0;

    lli n, k;
    cin >> n >> k;
    while(n--) {
        lli x;
        cin >> x;
        v.push_back(x);
    }
    // min heap
    make_heap(v.begin(), v.end(), greaters());
		// check if there's a minimum element < k
    if (v.front() < k) {
        while(v.size() > 1) {
            int firstMinVal = v.front();
            // delete min heap
            pop_heap(v.begin(), v.end(), greaters());
            v.pop_back();

            int secondMinVal = v.front();
            // delete min heap
            pop_heap(v.begin(), v.end(), greaters());
            v.pop_back();

            int formula = firstMinVal + (2*secondMinVal);
						// push heap
            v.push_back(formula);
            push_heap(v.begin(), v.end(), greaters());

            ans++;

            int minVal = v.front();
            if (minVal >= k) {
                break;
            }
        }
    }

    if (v.size() == 1 && v.front() < k) {
        cout << -1 << "\n";
    } else {
        cout << ans << endl;
    }


    return 0;
}