import java.util.Scanner;

public class Test {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt(), m = sc.nextInt(), idx, tmp;
		int[] t = new int[n];
		for (int i = 0; i < n; i++) {
			t[i] = i + 1;
		}
		for (int i = 0; i < m; i++) {
			idx = sc.nextInt() - 1;
			tmp = t[idx];
			for (int j = idx; j > 0; j--) {
				t[j] = t[j - 1];
			}
			t[0] = tmp;
		}
		System.out.println(t[0]);
	}
}