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

public class Main {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int N = scan.nextInt();
		int M = scan.nextInt();
		int []A = new int[M];
		ArrayList<Integer> list = new ArrayList<Integer>();
		for(int i = 0; i < M; i++) {
			A[i] = scan.nextInt();
		}
		scan.close();
		for(int i = 0; i < N; i++) {
			list.add(i + 1);
		}
		for(int i = 0; i < M; i++) {
			int temp = list.get(A[i] - 1);
			list.remove(A[i] - 1);
			list.add(M - 1, temp);
		}
		System.out.println(list.get(0));
	}

}