#include <bits/stdc++.h>
using namespace std;

int main() {
  int N, M;
  cin >> N >> M;
  vector<int> cards(N);

  for (int i = 0; i < N; i++)
    cards.at(i) = i + 1;

  for (int i = 0; i < M; i++) {
    int A;
    cin >> A;
    int tmp = cards.at(A - 1);
    cards.erase(cards.begin() + A - 1);
    cards.insert(cards.begin(), tmp);
  }

  cout << cards.at(0) << endl;
}