import java.util.Scanner;

public class Main {
	public static void main(String[] args) {

		try {
			Scanner scan = new Scanner(System.in);
			int N = scan.nextInt();
			int[] card = new int[N];
			int M = scan.nextInt();
			for(int i = 0; i < N; ++i){
				card[i] = i+1;
			}

			while(M-- > 0){
				int num = scan.nextInt()-1;
				int sw = card[num];
				for(int i = num; i > 0; --i){
					card[i] = card[i-1];
				}
				card[0] = sw;
			}

			System.out.println(card[0]);

			scan.close();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
}