#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using Graph = vector<vector<int>>;
int main() {
  int N,M; cin >> N >> M;
  vector<int> A(M);
  vector<int> X;
  for(int i = 0; i < M; i++) cin >> A[i];
  for(int i = 1; i <= N; i++) {
    X.push_back(i);
  }
  for(int i = 0; i < M; i++) {
    int x = X[A[i] - 1];
    X.erase(begin(X) + (A[i] - 1));
    X.insert(X.begin(), x);
  }
  cout << X[0] << endl;
}