#include <iostream>
#include <fstream>
using namespace std;
int main()
{
    ifstream fin("nrtri.in");
    ofstream fout("nrtri.out");
    int a[101],n,i,j,k,p;
    p=0;
    for(i=1;i<=n;i++)
        fin>>a[i];
    for(i=1;i<=n;i++)
        for(j=i+1;j<=n;j++)
            for(k=j+1;k<=n;k++)
                if(a[i]+a[j]>a[k]||a[j]+a[k]>a[i]||a[i]+a[k]>a[j])
                    p++;
    fout<<p;


}