#include <iostream>
#include <fstream>

#define MAXN 1010
using namespace std;

ifstream fin("nrtri.in");
ofstream fout("nrtri.out");

long A[MAXN];
long N;

inline bool isTri(int x,int y,int z) {
	return ((x <= (y + z)) && (y <= (x + z)) && (z <= (x + y)));
}

int main() {
	int i,j,k,res;
	res = 0;
	
	fin >> N;
	for (i=0;i<N;++i) 
		fin >> A[i];
		
	for (i=0;i<N-2;++i) {
		for (j=i+1;j<N-1;++j)
			for (k=j+1;k<N;++k)
				if (isTri(A[i],A[j],A[k])) res++;
	}
	
	fout << res << "\n";

	fin.close();
	fout.close();

	return 0;
}