#include<iostream>
using namespace std;
int main(void)
{
	int j, i, n, m, a, card[55],p;

	cin >> n >> m;
	for (i = 1; i <= n; i++) {
		card[i] = i;
	}
	for (i = 0; i < m; i++) {
		cin >> a;
		for (j = a; j > 1; j--) {
			p = card[j];
			card[j] = card[j - 1];
			card[j - 1] = p;
		}
	}
	cout << card[1] << endl;



	return 0;
}