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

#define int long long
#define PB push_back
#define PPB pop_back
typedef pair<int, int> pii;
typedef pair<double, double> pdd;

static const int INF = 1LL << 61;

int dp[100005], n, a[100005];

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(0);

    cin >> n;
    for (int i = n - 1; 0 <= i; --i) cin >> a[i];

    int ans = n;
    for (int i = 0; i < n; ++i) if (a[i] == ans) ans--;
    cout << ans << endl;
}