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

int main() {
    int n;
    cin >> n;
    vector<int> a(n);
    for (int i = 0; i < n; i++) cin >> a[i];

    int bottom = n;  
    int L = 0;
    for (int i = n - 1; i >= 0; i--) {
        if (a[i] == bottom) {
            L++;
            bottom--;
        } 
    }

    cout << n - L << endl;
    return 0;
}