RT

#include <bits/stdc++.h>
using namespace std;
long long n, k, ans = 0x3f3f3f3f;
double s, a[31];
map <double, pair <long long, long long> > maps;
void dfs(long long x, double sum, long long num){
	if (sum > s){
		return;
	}
	if (x >= n >> 1){
		maps[sum] = {1, num};
		return;
	}
	dfs(x + 1, sum + a[x], num);
	dfs(x + 1, sum + a[x] / 2, num + 1);
	dfs(x + 1, sum, num);
	return;
}
void dfs2(long long x, double sum, long long num){
    if (sum > s || num > ans){
		return;
    }
    if (x > n){
        if (maps[s - sum].first){
            ans = min(ans, maps[s - sum].second + num);
        }
        return;
	}
	dfs2(x + 1, sum + a[x], num);
	dfs2(x + 1, sum + a[x] / 2, num + 1);
	dfs2(x + 1, sum, num);
	return;
}
int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    cin >> n >> s;
	for (int i = 1; i <= n; i++){
		cin >> a[i];
	}
	dfs(1, 0, 0);
	dfs2(n >> 1, 0, 0);
	if (ans == 0x3f3f3f3f){
        cout << "-1";
	} else {
        cout << ans;
	}
	return 0;
}