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

typedef long long ll;

int main() {
	ll n, k, b, z = 0, needed = 0;
	cin >> n >> k >> b;
	vector<ll> pos;
	vector<ll> neg;
	for (int i = 0; i < n; i++) {
		ll x;
		cin >> x;
		if (!x) z++;
		else if (x > 0) pos.push_back(x);
		else {
			neg.push_back(x);
			needed -= x;
		}
	}
	if (b > neg.size()) {
		cout << -1;
		return 0;
	}
	sort(neg.begin(), neg.end());
	sort(pos.begin(), pos.end());
	for (int i = 0; i < b; i++) needed += neg[i];
	if (needed > k) {
		cout << -1;
		return 0;
	}
	k -= needed;
	z += neg.size() - b;
	if (k < z) {
		cout << 0;
		return 0;
	}
	k -= z;
	while (z--) pos.insert(pos.begin(), 1);
	int ptr = 0;
	while (k--) {
		pos[ptr]++;
		if (ptr == pos.size() - 1 || pos[ptr] <= pos[ptr + 1]) ptr = 0;
		else ptr++;
	}
	ll ans = 1;
	for (int x : pos) ans *= x;
	for (int i = 1; i <= b; i++) {
		ans *= neg[neg.size() - i];
	}
	cout << ans;
	return 0;
}