#include<iostream>
using namespace std;
int main()
{
    int n,v[100],i,j,m,k=0,gasit=0,aux;
    cout<<"n=";cin>>n;
    for(i=1;i<=n;i++)
    {
        cin>>v[i];
    }
    for(i=1;i<=n;i++)
    {
        do
        {
            gasit=0;
            if(v[i]>v[i+1])
            {
                aux=v[i];
                v[i]=v[i+1];
                v[i+1]=aux;
                gasit=1;
            }
        }while(gasit);
    }
    for(i=1;i<=n;i++)
   {
       for(j=i+1;j<=n;j++)
       {
           for(m=j+1;m<=n;m++)
            if(v[i]+v[j]>=v[m])
            k++;
       }
   }
   cout<<k;
}