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

int main() {
    int N;
    cin >> N;
    vector<int>P(N);
    long long sum = 0;
    for(int i = 0; i < N; i++) {
        cin >> P[i];
        sum += i+1;
        if(P[i] == N) {
            sum -= 2LL*(i+1);
        }
    }
    cout << max(0LL,sum) << endl;
}