#include <iostream>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <utility>
#include <string>

using namespace std;

int main() {
	int n, m, input;

	cin >> n >> m;
	string deck(n, '0');
	for (int i = 0; i < n; i++) {
		deck[i] = i + '1';
	}

	for (int i = 0; i < m; i++) {
		cin >> input;
		input--;
		deck = deck[input] + deck.substr(0, input) + deck.substr(input + 1);
	}

	int ans = deck[0] - '0';
	cout << ans << endl;
	return 0;
}