typedef long long ll;
typedef long double ld;
#include <bits/stdc++.h>
using namespace std;
#define int long long

signed main(){
    ll n;
    std::cin >> n;
    ll ans = n*(n+1)/2;
    for (int i = 0; i < n; i++) {
        ll p;
        std::cin >> p;
        if(p==n){
            ans -= 2*(i+1);
        }
    }
    if(n==1){
        std::cout << 0 << std::endl;
        return 0;
    }
    std::cout << ans << std::endl;
}