#include <iostream>
#include <vector>

using namespace std;

int main()
{
  int N;
  cin >> N;
  vector<int> vs( N );
  for( int i = 0; i < N; i++ ) {
	cin >> vs[ i ];
  }

  int v = N;
  for( int i = N - 1; i >= 0; i-- ) {
	// cout << vs[ i ] << ", " << v << endl;
	if ( vs[ i ] == v ) {
	  v--;
	}
  }

  cout << v << endl;  
}