#include <fstream>
using namespace std;
ifstream fin("nrtri.in");
ofstream fout("nrtri.out");
const int NMAX=801;
int v[NMAX];
int main()
{
    int n,sol=0;
    fin>>n;
    for(int i=1;i<=n;i++){
        fin>>v[i];
    }
    for(int i=1;i<=n;i++){
        for(int j=1;j<=n;j++){
            for(int y=1;y<=n;y++){
                if(v[i]+v[j]<=v[y] || v[i]+v[y]<=v[j] ||v[y]+v[j]<=v[i] ){
                    sol++;
                }
            }
        }
    }
    fout<<sol;
    return 0;
}