#include <bits/stdc++.h>
using namespace std;
long long GCD(long long a, long long b) {
  if (b == 0) return a;
  return (a % b == 0 ? b : GCD(b, a % b));
}
long long POW(long long base, long long exp) {
  long long val;
  val = 1;
  while (exp > 0) {
    if (exp % 2 == 1) {
      val = (val * base) % 1000000007;
    }
    base = (base * base) % 1000000007;
    exp = exp / 2;
  }
  return val;
}
bool acompare(long long int a, long long int b) { return a > b; }
int main() {
  long long int n, m, k, a[100], i = 0, f = 0;
  cin >> n >> m >> k;
  for (int i = 0; i < n; i++) cin >> a[i];
  sort(a, a + n, acompare);
  if (k != 0) {
    while (i < n) {
      if (k >= m) {
        f = 1;
        break;
      }
      k = k + a[i++] - 1;
    }
    if (f == 1)
      cout << i << endl;
    else {
      if (k >= m)
        cout << i << endl;
      else
        cout << "-1" << endl;
    }
  } else if (k == 0)
    cout << "-1" << endl;
  return 0;
}
