import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.StringTokenizer;

public class Main {

	public static void main(String[] args) throws NumberFormatException, IOException {
		Scanner sc = new Scanner();
		PrintWriter out = new PrintWriter(System.out);
		int n = sc.nextInt();
		int [] occ = new int[(int)1e5+1];
		for (int i = 0; i < n; ++i) {
			++occ[sc.nextInt()];
		}
		int cnt = n/2, i = 0;
		while(cnt > 0) {
			int val = Math.min(cnt, occ[i]);
			cnt -= val;
			occ[i] -= val;
			++i;
		}
		--i;
		// i contains (n/2)th element
		int k = 0;
		while(i < occ.length && occ[i++] == 0) ++k;
		out.println(k);
		out.flush();
		out.close();
	}

	static class Scanner {
		BufferedReader br;
		StringTokenizer st;

		public Scanner() {
			br = new BufferedReader(new InputStreamReader(System.in));
		}

		public String next() throws IOException {
			while (st == null || !st.hasMoreTokens()) {
				st = new StringTokenizer(br.readLine());
			}
			return st.nextToken();
		}

		public int nextInt() throws NumberFormatException, IOException {
			return Integer.parseInt(next());
		}
	}
}

/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz