#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; }