#include <iostream>
#include <fstream>

using namespace std;
ifstream f("nrtri.in");
ofstream g("nrtri.out");
int n,m,v[10],i,j,sume,a,b,k,poz,S,ll[4];

int main()
{

    f>>n;
    for(i=1;i<=n;i++)
    {
        f>>v[i];
    }
    sume=0; //cate sume sunt divizibile cu k

    for(i=1;i<=n-2;i++)
    {
        for(j=i+1;j<=n-1;j++)
        {
            for(k=j+1;k<=n;k++)
            {
                if((v[i]+v[j]>=v[k])&&(v[i]+v[k]>=v[j])&&(v[j]+v[k]>=v[i]))
                {
                    sume++;
                   // cout<<i<<j<<k<<endl;
                }
            }
        }
    }
        g<<sume;


    return 0;
}