#include <iostream>
#include <fstream>
#include <algorithm>
using namespace std;
ifstream fin("nrtri.in");
ofstream fout("nrtri.out");
int n,i,v[801],j,h,k;
inline bool triunghi(int a, int b, int c)
{
    return a+b>=c&&a+c>=b&&b+c>=a;
}
int main()
{
    fin>>n;
    for(i=1;i<=n;i++)
        fin>>v[i];
    //sort(v+1,v+n+1);
    for(i=1;i<n-1;i++)
        for(j=i+1;j<n;j++)
            for(h=j+1;h<=n;h++)
              if(triunghi(v[i],v[j],v[h]))
                       k++;
    fout<<k;
    return 0;
}