import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.*;
import java.math.*;
 
public class Main {
	public static void main(String[] args)throws IOException{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringBuilder sb = new StringBuilder();
		String[] str = br.readLine().split(" ");
		int n = Integer.parseInt(str[0]);
		int m = Integer.parseInt(str[1]);
		String[] str1 = br.readLine().split(" ");
		int[] deck = new int [n];
		for(int i = 0; i < n; i++)
			deck[i] = i+1;
		for(int i = 0; i < m; i++){
			int a = Integer.parseInt(str1[i]) -1;
			int tmp = deck[a];
			for(int j = a; j > 0; j--){
				deck[j] = deck[j-1];
			}
			deck[0] = tmp;
		}
		sb.append(deck[0]);
		System.out.println(sb);
	}
}