#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

int main()
{
	int n, k, b; cin >> n >> k >> b;
	vector<int> v(n);
	for (int i = 0; i < n; i++) cin >> v[i];

	sort(v.begin(), v.end());
	const int c = b;

	if (b != 0 && v[b - 1] >= 0){
		cout << -1;
		return 0;
	}
	if (n == b) b = 0;
	
	if (v[b + 1] - v[b] < k) {
		int r = b + 1;
		while (k - (r - b) * (v[r] - v[r - 1]) >= 0 && r < n) {
			k -= (r - b) * (v[r] - v[r - 1]);
			++r;
		}
		--r;

		for (int i = b; i < r; ++i) 
			v[i] = v[r];
		for (int i = b; i <= r; ++i) 
			v[i] += k / (r - b + 1);

		k = k % (r - b + 1);
		for (int i = b; i < b + k; ++i)
			++v[i];
	}
	else {
		v[b] += k;
	}

	if (n == c) {
		for (int i = 0; i < n; ++i) {
			if (v[i] >= 0) {
				cout << -1; 
				return 0; 
			}
		}
	}
	else if (v[b] < 0) {
		cout << -1;
		return 0;
	}

	long long p = 1; 
	int mod = 1000000007;
	for (int i = 0; i < n; i++)
		p = (p * v[i]) % mod;
	cout << p;

	return 0;
}