source_code: import java.io.*;
  import java.util.*;
  
  public class A {
  
  	BufferedReader in;
  	StringTokenizer st;
  	PrintWriter out;
  
  	String next() throws IOException {
  		while (st == null || !st.hasMoreTokens())
  			st = new StringTokenizer(in.readLine());
  		return st.nextToken();
  	}
  
  	int nextInt() throws Exception {
  		return Integer.parseInt(next());
  	}
  
  	long nextLong() throws Exception {
  		return Long.parseLong(next());
  	}
  
  	double nextDouble() throws Exception {
  		return Double.parseDouble(next());
  	}
  
  	void solve() throws Exception {
  		int n = nextInt(), k = nextInt(), s = nextInt();
  		int a[] = new int[n];
  		for (int i = 0; i < n; i++)
  			a[i] = -nextInt();
  		
  		Arrays.sort(a);
  		for(int i=0;i<n;i++)
  		{
  			if (s>=k)
  			{
  				out.println(i);
  				return;
  			}
  			
  			s += -a[i];
  			s--;
  		}
  		if (s<k)
  			out.println(-1);
  		else
  			out.println(n);
  	}
  
  	void run() {
  		try {
  			Locale.setDefault(Locale.US);
  			in = new BufferedReader(new InputStreamReader(System.in));
  			out = new PrintWriter(new OutputStreamWriter(System.out));
  			solve();
  			out.close();
  		} catch (Exception e) {
  			e.printStackTrace();
  			System.exit(1);
  		}
  	}
  
  	public static void main(String[] args) {
  		new A().run();
  	}
  
  
  }
  