#include <fstream>
#include <cstdio>
#include <iostream>
#include <algorithm>

using namespace std;
ofstream g("nrtri.out");
int n,u,i,x[10001],j,m,fr[60003],nr[60003],k,pa,pozi[60003],s[123000];
long long sol;

__attribute__((always_inline)) void read(int &num)
{
    static char inBuffer[0x30D40];

    static unsigned int p = 0x30D3F; num = 0x0;

    while(inBuffer[p] < 0x30 | inBuffer[p] > 0x39)
    {
        ++p != 0x30D40 || (fread(inBuffer, 0x1, 0x30D40, stdin), p = 0x0);
    }

    while(inBuffer[p] > 0x2F & inBuffer[p] < 0x3A)
    {
        num = num * 0xA + inBuffer[p] - 0x30;

        ++p != 0x30D40 || (fread(inBuffer, 0x1, 0x30D40, stdin), p = 0x0);
    }
}

char outBuffer[0x61A80]; unsigned int p;

__attribute__((always_inline)) void write(unsigned int x)
{
    unsigned int digits = x > 0x3B9AC9FF ? 0xA :
                 x > 0x5F5E0FF  ? 0x9 :
                 x > 0x98967F   ? 0x8 :
                 x > 0xF423F    ? 0x7 :
                 x > 0x1869F    ? 0x6 :
                 x > 0x270F     ? 0x5 :
                 x > 0x3E7      ? 0x4 :
                 x > 0x63       ? 0x3 :
                 x > 0x9        ? 0x2 : 0x1;

    for(unsigned int i = ~-digits; ~i; --i)
    {
        outBuffer[p + i] = x % 0xA + 0x30;

        x = x / 0xA;
    }

    p = p + digits; outBuffer[p++] = 0x20;
}

int main ()
{
    freopen("nrtri.in", "r", stdin);

    read(n);
    m = 0;
    for(i = 1; i <= n; i++)
    {
        read(x[i]);
        fr[x[i]]++;
        if(x[i] > m) m = x[i];
    }
    j = 0;
    for(i = 1; i <= m; i++)
       for(u = 1; u <= fr[i]; u++)
       {
           j++;
           x[j] = i;
       }
    k = 1;
    while(x[k]+x[k+1]<=m)k++;
    k--;
    pa = n;
    while(x[1]+x[pa]>m)pa--;
    pozi[1] = pa;
    for(i = 2; i <= k; i++)
    {
        while(x[i]+x[pa]>m)pa--;
        pozi[i] = pa;
    }
    for(i = 1; i <= k ; i++)
        for(j = i+1; j <= pozi[i]; j++)
            s[x[i]+x[j]]++;
    for(i = m; i >= 1; i--)
        nr[i] = nr[i+1] + fr[i];
    sol = 0;
    for(i = 1; i <= m; i++)
        sol += s[i]*nr[i];
    g << 1LL*n*(n-1)*(n-2)/6-sol;
    return 0;
}