#include <bits/stdc++.h>
using namespace std;
int dx[] = {0, 0, 1, -1, 1, -1, 1, -1};
int dy[] = {1, -1, 0, 0, -1, 1, 1, -1};
long long gcd(long long a, long long b) { return !b ? a : gcd(b, a % b); }
long long lcm(long long a, long long b) { return (a / gcd(a, b)) * b; }
long long power(unsigned long long a, unsigned long long b,
                unsigned long long ret = 1LL) {
  while (b--) ret = (ret * a);
  return ret;
}
int main() {
  int n, m, k;
  cin >> n >> m >> k;
  vector<int> filters(n);
  for (int i = 0; i < n; i++) {
    cin >> filters[i];
  }
  sort(filters.rbegin(), filters.rend());
  int totalSockets = k;
  int usedFilters = 0;
  int unUsedFiltersPos = 0;
  if (totalSockets >= m) {
    cout << usedFilters;
  } else {
    bool can = false;
    while (k-- && unUsedFiltersPos < n && !can) {
      totalSockets += filters[unUsedFiltersPos++] - 1;
      if (totalSockets >= m) can = true;
      usedFilters++;
    }
    while (unUsedFiltersPos < n && !can) {
      totalSockets += filters[unUsedFiltersPos++] - 1;
      if (totalSockets >= m) can = true;
      usedFilters++;
    }
    if (can) {
      cout << usedFilters;
    } else
      cout << -1;
  }
}
