import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int counter = n;
        int[] types = new int[n];
        for(int types_i=0; types_i < n; types_i++){
            types[types_i] = in.nextInt();
        }
        // your code goes here
        for(int types_i=0; types_i < n; types_i++) {
            for(int types_j=0; types_j < types_i; types_j++) {
                if(types[types_i] == types[types_j]) {
                    counter--;
                }
            }       
        }
        System.out.println(types[counter]);
    }
}