import java.util.Scanner;
import java.util.Arrays;
class a{
    public static void main(String[] b){
        Scanner sc=new Scanner(System.in);
		int N=sc.nextInt();
		int M=sc.nextInt();
		int shaf[]=new int[M], card[]=new int[N];
		int tmp;
		
		for(int i=0; i<M; i++){
			shaf[i]=sc.nextInt();
		}
		for(int i=0; i<N; i++){
			card[i]=i+1;
		}
		for(int i=0; i<M; i++){
			tmp=card[shaf[i]-1];
			for(int j=shaf[i]-2; j>=0; j--){
				card[j+1]=card[j];
			}
			card[0]=tmp;
		}
		System.out.println(card[0]);
    }
}