#include<fstream>

using namespace std;

int n,p,a[100];
int main()
{
    ifstream fin("nrtri.in");
    ofstream fout("nrtri.out");

int i,j;
fin>>n;
for(i = 1; i <= n; i++)
fin>>a[i];
for(i = 1; i <= n; i++)
{
    for(j = 1; j <= n; j++)
    if(a[i]+a[i+1] > a[j] && a[i]+a[j] > a[i++] && a[i+1]+a[j]>a[i])
        p++;
}
fout<<p;

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

return 0;

}