#include <bits/stdc++.h>
using namespace std;
int f[55];
int main() {
  int N, M, K;
  scanf("%d %d %d", &N, &M, &K);
  for (int i = 0; i < N; i++) scanf("%d", &f[i]);
  sort(f, f + N);
  int total = K;
  for (int i = 0; i <= N; i++) {
    if (total >= M) {
      printf("%d\n", i);
      break;
    } else if (i == N) {
      printf("-1\n");
      break;
    }
    total += f[N - i - 1] - 1;
  }
}
