#include <bits/stdc++.h>
#define rep(i,a,n) for(int i=a;i<n;i++)
#define repb(i,a,b) for(int i=a;i>=b;i--)
#define all(a) a.begin(),a.end()
#define o(a) cout<<a<<endl
#define int long long
#define fi first
#define se second
using namespace std;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int,int> pii;

signed main(){
	int n;
	cin>>n;
	vi d(n);
	rep(i,0,n) cin>>d[i];
	int MAX=d[0];
	int cnt=1;
	rep(i,1,n){
		if(d[i]==MAX+1) cnt++;
		else if(d[i]>MAX) cnt=1;
		MAX=max(MAX,d[i]);
	}
	cout<<n-cnt<<endl;
}