#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

const ll MOD = 1e9 + 7;

int main()
{
    ll n, m, b;
    cin >> n >> m >> b;

    vector<ll> alap(n);
    ll van = 0;
    for(ll &x : alap){
        cin >> x;
        van += (x < 0);
    }

    if(van < b){
        cout << "-1\n";
        return 0;
    }

    sort(alap.begin(), alap.end());

    ll l = 0, r = 1e9 + 2e5;
    ll val = -1;
    ll mar = 0;

    while(l <= r){
        ll k = (l + r) / 2;

        ll ossz = 0;
        for(ll i = b; i < n; i++){
            ossz += max(0ll, k - alap[i]);

            if(ossz > m) break;
        }

        if(ossz <= m){
            val = k;
            mar = m - ossz;
            l = k + 1;
        } else{
            r = k - 1;
        }
    }

    if(val == -1){
        cout << "-1\n";
        return 0;
    }

    for(ll i = b; i < n; i++){
        alap[i] = max(alap[i], val);
        if(mar > 0){
            alap[i]++;
            mar--;
        }
    }

    assert(mar == 0);

    ll ans = 1;
    for(ll x : alap){
        x %= MOD;

        ans *= x;
        ans %= MOD;
    }

    cout << ans << "\n";
}