#include <bits/stdc++.h>
using namespace std;
#define REP(i, init, n) for(int i = (int)(init); i < (int)(n); i++)

int main() {
    int N;
    cin>>N;
    vector<int> A(N, 0);
    REP(i, 0, N) cin>>A[i];
    int Amax = N; int count = 0;
    for(int i=N-1; i >= 0; i--){
        if(A[i] == Amax){
            Amax--;
            count++;
        }
    }
    cout << N-count << endl;
}