#include <bits/stdc++.h>
using namespace std;

#ifdef _RUTHEN
#include "debug.hpp"
#else
#define show(...) true
#endif

using ll = long long;
#define rep(i, n) for (int i = 0; i < (n); i++)
template <class T> using V = vector<T>;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    ll N, K;
    cin >> N >> K;
    V<ll> A(N);
    rep(i, N) cin >> A[i];
    V<V<int>> dp1(N + 1, V<int>(K + 1, 0)), dp2(N + 1, V<int>(K + 1, -1));
    dp1[0][0] = 1;
    rep(i, N) {
        for (int k = 0; k <= K; k++) {
            if (dp1[i][k] == 0) continue;
            dp1[i + 1][k] = 1;
            dp2[i + 1][k] = k;
            if (k + A[i] <= K) {
                dp1[i + 1][k + A[i]] = 1;
                dp2[i + 1][k + A[i]] = k;
            }
        }
    }
    show(dp1, dp2);
    if (dp1[N][K] == 0) {
        cout << -1 << '\n';
        return 0;
    }
    set<int> S;
    int k0 = K;
    for (int i = N; i > 0; i--) {
        if (dp2[i][k0] != k0) {
            // add
            S.insert(i - 1);
            k0 = dp2[i][k0];
        }
    }
    V<V<int>> dp3(N + 1, V<int>(K + 1, 0));
    dp3[0][0] = 1;
    rep(i, N) {
        for (int k = 0; k <= K; k++) {
            if (dp3[i][k] == 0) continue;
            dp3[i + 1][k] = 1;
            if (k + A[i] <= K && S.count(i) == 0) {
                dp3[i + 1][k + A[i]] = 1;
            }
        }
    }
    int ans = 0;
    for (auto &s : S) {
        if (dp3[N][A[s]] == 0) {
            ans++;
        }
    }
    show(S);
    cout << ans << '\n';
    return 0;
}