#include <iostream>
#include <fstream>
using namespace std;

int main()
{
    ifstream f("numere.in");

    int n, m, aux, nr = 0, l = 1;

    f >> n >> m;

    int v[n], indice[10];

    for(int i = 1; i <= n; i++)
        f >> v[i];

    for(int i = 0; i < 9; i++)
        indice[i] = 0;

    for(int i = 1; i <= m + 1; i++) {
        for(int j = i + 1; j <= n; j++) {
            aux = v[i] + v[j];
            indice[aux] = 1;
        }
    }

    for(int i = 0; i < 9; i++)
        if(indice[i] == 1)
            nr++;
    cout << nr;
}