#include <iostream>
#include <fstream>
using namespace std;
ifstream fi("nrtri.in");
ofstream fo("nrtri.out");
int i,j,q,k=0,s[800],n;
int tr(int a,int b,int c)
{
    if(a+b>=c and a+c>=b and b+c>=a)
        return 1;
    else
        return 0;
}
int main()
{
   fi>>n;
   for(i=1;i<=n;i++)
        fi>>s[i];
   for(i=1;i<n-1;i++)
    {
        for(j=i+1;j<n;j++)
        {
            q=j+1;
            while(q<=n)
            {
                if(tr(s[i],s[j],s[q])==1)
                    k++;
                q++;
            }
        }
    }
    fo<<k;
    return 0;
}