import java.util.*;
import java.math.*;
import java.io.*;

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