#include<fstream>
#include<algorithm>
using namespace std;
ifstream cin("nrtri.in");
ofstream cout("nrtri.out");
short a[800],n,i,aux;
int rs;
bool comp(short a,short b){
	return a>b;
}
int main(){
	cin>>n;
	for(i=0;i<n;i++)cin>>a[i];
	sort(a,a+n,comp);
	for(i=0;i<n;i++){
		aux=i+1;
		while(a[i]<=(a[aux]+a[aux+1])){
			aux++;
			rs++;
		}
	}
	cout<<rs;
	return 0;
}