#include <bits/stdc++.h>

using namespace std;
using ll = long long;

int main(){

    ll N, e, ans=0;
    cin >> N;
    vector<vector<ll>> p(9, vector<ll>(9));
    vector<ll> cnt(9);

    for (int i=1; i<=8; i++){
        e = 1;
        for (int j=1; j<=8; j++){
            e *= i;
            p[i][j] = e;
        }
    }

    for (int i=0; i<N; i++){
        cin >> e;
        cnt[e]++;
    }

    for (int i=1; i<=8; i++){
        for (int j=1; j<=8; j++){
            ans += cnt[i]*cnt[j]*p[i][j];
        }
    }

    cout << ans << endl;

    return 0;
}