import java.util.Arrays;
import java.util.LinkedList;
import java.util.Scanner;

public class Main {
	
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		
		final int N = sc.nextInt();
		final int M = sc.nextInt();
	
		int[] deck = new int[N];
		for(int i = 0; i < N; i++){
			deck[i] = i + 1;
		}
		
		for(int i = 0; i < M; i++){
			final int A = sc.nextInt() - 1;
			final int top = deck[A];
			
			for(int j = A; j > 0; j--){
				deck[j] = deck[j - 1];
			}
			deck[0] = top;
		}
		
		System.out.println(deck[0]);
		
	}
	
}