#include <iostream>
#include <fstream>
using namespace std;
int nr;
int main()
{   int n,i,v[100],j,k;
    ifstream f("nrtri.in");
    ofstream g("nrtri.out");
    cin>>n;
    for(i=1;i<=n;i++)
        cin>>v[i];
    for(i=1;i<=n;i++)
        for(j=i+1;j<=n;j++)
            for(k=j+1;k<=n;k++)
                if(v[i]+v[j]>v[k])
                    if(v[i]+v[k]>v[j])
                        if(v[j]+v[k]>v[i])
                            {nr++; cout<<"aici"<<'\n';}
    cout<<nr;
    f.close();
    g.close();
    return 0;
}