import java.util.Scanner;
import java.util.ArrayList;

public class yukicoder_123 {
	public static void main(String[] args) {
		Scanner stdIn = new Scanner(System.in);
		
		int n = stdIn.nextInt();
		int m = stdIn.nextInt();
		
		int[] a = new int[m];
		
		for (int i = 0; i < m; i++) {
			a[i] = stdIn.nextInt();
		}
		
		ArrayList<Integer> list = new ArrayList<Integer>(50);
		
		for (int i = 1; i <= n; i++) {
			list.add(i);
		}
		
		for (int i = 0; i < m; i++) {
			Integer x = list.get(a[i] - 1);
			list.remove(a[i] - 1);
			list.add(0, x);
		}
		
		System.out.println(list.get(0));
	}
}