#include <iostream>
#include <vector>
using namespace std;

int main()
{
	int n, m;
	cin >> n >> m;

	vector<int>card(n);
	for (int i = 0; i < n; i++) card[i] = i + 1;
	for (int i = 0; i < m; i++) {
		int a;
		cin >> a;
		card.insert(card.begin(), card[a-1]);
		card.erase(card.begin() + a);
	}

	cout << card.front() << endl;

    return 0;
}