/* -*- coding: utf-8 -*-
 *
 * 2203.cc:  No.2203 POWER!!!!! - yukicoder
 */

#include<cstdio>
#include<algorithm>
 
using namespace std;

/* constant */

const int MAX_A = 8;

/* typedef */

typedef long long ll;

/* global variables */

int cs[MAX_A + 1];

/* subroutines */

int powi(int a, int b) {
  int p = 1;
  while (b > 0) {
    if (b & 1) p *= a;
    a *= a;
    b >>= 1;
  }
  return p;
}

/* main */

int main() {
  int n;
  scanf("%d", &n);

  for (int i = 0; i < n; i++) {
    int ai;
    scanf("%d", &ai);
    cs[ai]++;
  }

  ll sum = 0;
  for (int x = 1; x <= MAX_A; x++)
    for (int y = 1; y <= MAX_A; y++)
      sum += (ll)powi(x, y) * cs[x] * cs[y];

  printf("%lld\n", sum);
  return 0;
}