#include <fstream>
using namespace std; ifstream in("nrtri.in"); ofstream out("nrtri.out");

const int N=801;
short v[N],n;

bool triunghi(int x,int y,int z){
    if((x+y>=z) && (x+z>=y) && (y+z>=x)){
        return true;
    }
    return false;
}
int verifica(){
    int nr=0;
    for (int i = 0; i < n; i++) {
        for (int j = i+1; j < n; j++) {
            for (int k = j+1; k < n; k++) {
                if (triunghi(v[i],v[j],v[k]))
                    ++nr;
            }
        }
    }
    return nr;
}
int main(){
    in>>n;
    for (int i = 0; i < n; i++) {
        in>>v[i];
    }
    out<<verifica();
    return 0;
}