#include <iostream>
#include <algorithm>
#include <vector>
#include <numeric>
using namespace std;
int main() {
	int N;
	int M;
	cin >> N >> M;
	vector<int> v(N, 0);
	iota(v.begin(), v.end(), 1);

	for (int i = 0; i < M;i++) {
		int A; cin >> A;
		int temp = v[A - 1];
		v.erase(v.begin() + (A - 1));
		v.insert(v.begin(), temp);
	}
	cout << v[0] << endl;
	return 0;
}