#include <bits/stdc++.h>
using namespace std;
int n, b, c, a[100], m;
int main() {
  scanf("%d%d%d", &n, &b, &c);
  for (int i = 0; i < n; ++i) scanf("%d", &a[i]);
  m = c;
  sort(a, a + n);
  for (int i = n - 1; i >= 0; --i) {
    if (m >= b) {
      printf("%d", n - 1 - i);
      return 0;
    }
    m += a[i] - 1;
  }
  if (m >= b)
    printf("%d", n);
  else
    puts("-1");
  return 0;
}
