#include <iostream>
#include <fstream>
using namespace std;
ifstream in("nrtri.in");
ofstream out("nrtri.out");
int v[803],n,i,j,k,sol;
void citire()
{
    in>>n;
    for(i=1;i<=n;i++)in>>v[i];
}

int triunghi(int a,int b,int c)
{
    if(a+b>=c&&a+c>=b&&b+c>=a)return 1;
    else return 0;
}

int main()
{
    citire();
    for(i=1;i<=n-2;i++)
    {
        for(j=i+1;j<=n-1;j++)
        {
            for(k=j+1;k<=n;k++)
                if(triunghi(v[i],v[j],v[k]))sol++;

        }
    }
    out<<sol;
    return 0;
}