#include <iostream>

#include <vector>
using namespace std;

int main(){


  int n,m;
  cin >> n >> m;
  vector<int> v;
  for (int i = 0; i < n; i++) {
    v.push_back(i + 1);
  }
  for (int i = 0; i < m; i++) {
    int a;
    cin >> a;
    int tmp = v[a - 1];
    for (int i = 0; i < a - 1; i++) {
      v[a - 1 - i] = v[a - 2 - i];
    }
    v[0] = tmp;
  }
  cout << v[0] << "\n";
  return 0;
}