#include "bits/stdc++.h"
using namespace std;
#define rt return
#define FOR(i,j,k) for(int i=j; i<(int)k;++i)
#define rep(i,j) FOR(i,0,j)
#define each(x,y) for(auto &(x):(y))
#define mp make_pair
#define mt make_tuple
#define all(x) (x).begin(),(x).end()
#define debug(x) cout<<#x<<": "<<(x)<<endl
#define smax(x,y) (x)=max((x),(y))
#define smin(x,y) (x)=min((x),(y))
#define MEM(x,y) memset((x),(y),sizeof (x))
#define sz(x) (int)(x).size()
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
#define N_MAX 100001
int N, a[N_MAX], p[N_MAX], ans = 0;
int main(){
    ios::sync_with_stdio(0);
    cin.tie(0);
    cin >> N;
    rep(i, N)cin >> a[i + 1];
    int cur = N;
    for(int i = N; i >= 1; --i){
        if(a[i] == cur){
            --cur;
        } else{
            ++ans;
        }
    }
    cout << ans << endl;
}