#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include <map>
#include <vector>
#include <queue>
#include <deque>
#include <set>
#include <stack>
#include <algorithm>
#include <array>
#include <unordered_set>
#include <unordered_map>
#include <string>
using namespace std;

bool rcmp(int a, int b) { return a>b; }
typedef long long LL;



int main() {
    int n, i, v, j, k;
    LL r=0, t;
    int cs[10];
    for (i=1; i<=8; i++) cs[i]=0;
    scanf("%d", &n);
    for (i=0; i<n; i++) {
        scanf("%d", &v); cs[v]++;
    }
    for (i=1; i<=8; i++) for (j=1; j<=8; j++) {
        t=1;
        for (k=0; k<j; k++) t*=i;
        t*=cs[i]; t*=cs[j];
        r+=t;
    }
    printf("%lld\n", r);
    return 0;
}