#include <bits/stdc++.h>

using namespace std;
#define fast_io ios_base::sync_with_stdio(false), cin.tie(NULL), cout.tie(NULL)
#define pb push_back
#define ll long long
#define ld long double

#define rep(i, n) for (ll i=0; i<n; i++)
#define repi(i, n) for (ll i=1; i<=n; i++)

#define repi1(i, n) for (ll i = n; i >=0; i--)
#define mem(v, ha) memset(v, ha, sizeof(v))
#define all(a)  a.begin(), a.end()
#define allr(a)  a.rbegin(), a.rend()
#define CLOCK cerr << "\nTime elapsed: " << 1000 * clock() / CLOCKS_PER_SEC << "ms\n";
typedef vector<ll> vi;
typedef vector<vector<int>> vvi;
typedef vector<pair<ll, ll>> vpi;
typedef vector<char> vc;
#define no cout << "NO\n"
#define yes cout << "YES\n"
#define mp make_pair
#define ff first
#define ss second
const ll mod = 1e9 + 7;
//const ll mod = 998244353 ;

// const long double PI = 3.141592653589793238460;
// const int inf = (int)(1e9);

// template<typename T> istream& operator>>(istream& in, vector<T>& a) {for (auto &x : a) in >> x; return in;};
// template<typename T> ostream& operator<<(ostream& out, vector<T>& a) {for (auto &x : a) out << x << ' '; return out;};



// // auto sum=[&](int use, int y){return use+y;};
// // function <void(int)>dfs=[&](int u)
// //void is the return type, int is the argumen


// void solve()
// {

// }

// int32_t main()
// {

// // #ifndef ONLINE_JUDGE
// //     freopen("input.txt", "r", stdin);
// //     freopen("oo.txt", "w", stdout);
// // #endif

//     fast_io;
//     int T = 1;

//     cin >> T;

//     while (T--)
//     {
//         solve();


//     }

// }


int main() {
    int n;
    cin >> n;
    vi a(n);
    rep(i, n)
    cin >> a[i];
    int t = n;
    int ans = 0;
    if (is_sorted(all(a)))
    {
        cout << 0 << '\n';

    }
    else
    {


        for (int i = n - 1; i >= 0; i--)
        {
            if (a[i] == t)
            {
                t--;
                ans++;
            }
        }
        cout << n - ans << '\n';
    }
}