#include <cstdio>
#include <algorithm>
using namespace std;
int v[800] ,f[800] ;
int cnt ;
int main()
{
    freopen("nrtri.in","r",stdin) ;
    freopen("nrtri.out","w",stdout) ;
    int n ,i ,j ,k ,sum ;
    scanf("%d",&n) ;
    for (i = 1 ; i <= n ; ++ i){
        scanf("%d",&v[i]) ;
        f[v[i]] ++ ;
    }
    sort(v + 1 ,v + 1 + n) ;
    for (i = 1 ; i <= n ; ++ i){
        for (j = i + 1 ; j <= n ; ++ j){
            sum = v[i] + v[j] ;
                for (k = j + 1 ; k < sum ; ++ k)
                    if (f[v[k]] != 0 && v[i] + v[j] >= v[k]) cnt ++ ;
        }
    }
    printf("%d",cnt) ;
    return 0;
}