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

int main(){
  int n; cin >> n;
  vector<int> a(n);
  for(int i = 0; i < n; i++) cin >> a[i];
  reverse(a.begin(), a.end());
  int at = n;
  int cnt = 0;
  for(int i = 0; i < n; i++){
    if(a[i]==at){
      at--;
      cnt++;
    }
  }
  int ans = n - cnt;
  cout << ans << endl;
  return 0;
}