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

signed main(){
  int N, M; cin >> N >> M;
  deque< int > dq;
  for( int i = 1; i <= N; ++i )
    dq.emplace_back( i );
  for( int i = 0; i < M; ++i ){
    int A; cin >> A;
    int v = dq[ A - 1 ];
    dq.erase( dq.begin() + A - 1 );
    dq.emplace_front( v );
  }
  cout << dq.front() << endl;
  return 0;
}