#include <iostream>
#include <string>

using namespace std;

int main(int argc, const char* argv[])
{
	int N, M;
	cin >> N >> M;
	string s;
	for (int i = 0; i < N; i++) {
		s += (char)(i + 1);
	}
	int A[M];
	int a;
	for (auto&& a : A) {
		cin >> a;
		char tmp = s[a - 1];
		s.erase(s.begin() + (a - 1));
		s = tmp + s;
	}
	cout << (int)s[0] << endl;
	return 0;
}