#include<bits/stdc++.h>
using namespace std;
using ll=long long;
using pii=pair<int,int>;

#define all(a) a.begin(),a.end()
#define pb push_back
#define sz(a) ((int)a.size())

int cnt[10];

signed main(){
    ios_base::sync_with_stdio(0),cin.tie(0);
    int n; cin >> n;
    for(int i=0; i<n; ++i){int x; cin >> x; cnt[x]++;}
    ll res=0;
    for(int i=1; i<=8; ++i) for(int j=1; j<=8; ++j){
        int de=1;
        for(int k=0; k<j; ++k) de*=i;
        res+=1ll*cnt[i]*cnt[j]*de;
    }
    cout << res << "\n";
}