#include <bits/stdc++.h>
using namespace std;

using ull = uint64_t;
using ll = int64_t;
using vi = vector<int>;
using vll = vector<ll>;
using vs = vector<string>;
using ld = long double;
using P = pair<ll,ll>;
using G = vector<vector<int>>;

#define LO(...) (void)0
#define debug(x) (void)0

#define reps(i,a,n) for(ll i##_len = (ll)(n), i = (a); i < i##_len; ++i)
#define rep(i,n) reps(i,0,(n))
#define rrep(i,n) reps(i,1,(n)+1)
#define repd(i,n) for(ll i=(n)-1;i>=0;i--)
#define rrepd(i,n) for(ll i=(n);i>=1;i--)

#define inp(i) ll i; cin >> i;
#define inps(s) string s; cin >> s;
#define inpp(p) cin >> (p).first >> (p).second
#define inpv(v,N) vll v(N);rep(i,N)cin>>v[i];
#define inpvs(v,N) vs v(N);rep(i,N)cin>>v[i];
#define all(v) begin(v),end(v)
#define Yes cout<<"Yes\n"
#define No cout<<"No\n"
#define allok(i,N,pred) [&]()->bool{bool allok_=1;rep(i,N)if(!(pred))allok_=0;return allok_;}()
#define anyok(i,N,pred) [&]()->bool{bool anyok_=0;rep(i,N)if(pred)anyok_=1;return anyok_;}()
void YESNO(bool b){cout<<(b?"YES\n":"NO\n");}void yesno(bool b){cout<<(b?"yes\n":"no\n");}void YesNo(bool b){cout<<(b?"Yes\n":"No\n");}

#define SP cout << " "
#define ENDL cout << "\n"
#define setfp cout << fixed << setprecision(16)
template<typename C>void ou(const C&v){cout<<v;}
template<typename C>void ous(const C&v){cout<<v<<" ";}
template<typename C>void oul(const C&v){cout<<v<<"\n";}

template<typename C>void ouv(const C &v){for(auto &&e:v){cout << e;if(&e != &v.back()) cout << ' ';}cout << "\n";}
template<typename C>void ouvadd(const C &v){for(auto &&e:v){cout << e+1;if(&e != &v.back()) cout << ' ';}cout << "\n";}

template<typename T>bool chmax(T &a, const T &b){return a<b?(a=b,1):0;}
template<typename T>bool chmin(T &a, const T &b){return b<a?(a=b,1):0;}

template<typename T>void so(T &a){sort(begin(a),end(a));}
template<typename T,typename C>void so(T &a,C c){sort(begin(a),end(a),c);}
template<typename T>void rso(T &a){sort(rbegin(a),rend(a));}
template<typename T,typename C>void rso(T &a,C c){sort(rbegin(a),rend(a),c);}

constexpr ll INF = 1e18;

ll ipow(ll a, ll b){
    ll r = 1;
    rep(i,b){
        r *= a;
    }
    return r;
}

int main() {
    inp(N);
    inpv(a,N);
    map<ll,ll> s;
    rep(i,N)s[a[i]]++;

    ll ans = 0;
    rep(i,8){
        rep(j,8){
            ans += ipow(i+1,j+1) * s[i+1] * s[j+1];
        }
    }
    oul(ans);
}