#include <bits/stdc++.h>
#include <cassert>
#include <cmath>
#include <complex>
using namespace std;
#include <atcoder/all>
using namespace atcoder;
using ll = long long;
using vll = vector<ll>;
using vvll = vector<vll>;
using vvvll = vector<vvll>;
#define all(A) A.begin(),A.end()
#define rep(i, n) for (ll i = 0; i < (ll) (n); i++)
template<class T>
bool chmax(T& p, T q, bool C = 1) {
    if (C == 0 && p == q) {
        return 1;
    }
    if (p < q) {
        p = q;
        return 1;
    }
    else {
        return 0;
    }
}

template<class T>
bool chmin(T& p, T q, bool C = 1) {
    if (C == 0 && p == q) {
        return 1;
    }
    if (p > q) {
        p = q;
        return 1;
    }
    else {
        return 0;
    }
}

ll gcd(ll(a), ll(b)) {
    if (a == 0)return b;
    if (b == 0)return a;
    ll c = a;
    while (a % b != 0) {
        c = a % b;
        a = b;
        b = c;
    }
    return b;
}
ll sqrtz(ll N) {
    ll L = 0;
    ll R = sqrt(N) + 10000;
    while (abs(R - L) > 1) {
        ll mid = (R + L) / 2;
        if (mid * mid <= N)L = mid;
        else R = mid;
    }
    return L;

}


using mint = modint998244353;




int main() {

    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    ll N;
    cin>>N;
    vll A(9,0);
    rep(i,N){
        ll a;
        cin>>a;
        A[a]++;
    }
    ll an=0;
    for(ll i=1;i<=8;i++){
        for(ll j=1;j<=8;j++){
            ll r=1;
            rep(k,j)r*=i;
            an+=r*A[i]*A[j];
        }
    }
    cout<<an<<endl;
}