#include<bits/stdc++.h>
using namespace std;
int a[100000];
int main(){
  int n;
  cin>>n;
  int maxx=-1;
  int maxc=1;
  for(int i=0;i<n;i++){
    cin>>a[i];
  }
  maxx=a[n-1];
  for(int i=n-1;i>=0;i--){
    //cout<<a[i]<<endl;
    if(maxx-1 == a[i]){
      maxc++;
      maxx = a[i];
    }
  }

  cout<<n-maxc<<endl;
}