#include <bits/stdc++.h>
#define rep(i, l, r) for (int i = (l); i < (r); i++)
using namespace std;

typedef long long ll;

int main() {
    int N;
    cin >> N;
    vector<int> P(N);
    rep(i, 0, N) cin >> P[i];
    if (N == 1) {
        cout << 0 << endl;
        return 0;
    }
    if (N == 2) {
        if (P[0] == 1) cout << 0 << endl;
        else cout << 1 << endl;
        return 0;
    }
    ll ans = 0;
    rep(i, 0, N) {
        if (P[i] == N) ans -= i + 1;
        else ans += i + 1;
    }
    cout << ans << endl;
}