Write a python function to count the maximum number of equilateral triangles that can be formed within a given equilateral triangle.
def No_of_Triangle(N,K):
    if (N < K):
        return -1;
    else:
        Tri_up = 0;
        Tri_up = ((N - K + 1) *(N - K + 2)) // 2;
        Tri_down = 0;
        Tri_down = ((N - 2 * K + 1) *(N - 2 * K + 2)) // 2;
        return Tri_up + Tri_down;
<s>[INST]<<SYS>>Given a task and its code, generate test cases for the code.<</SYS>>Write a python function to count the maximum number of equilateral triangles that can be formed within a given equilateral triangle.
def No_of_Triangle(N,K):
    if (N < K):
        return -1;
    else:
        Tri_up = 0;
        Tri_up = ((N - K + 1) *(N - K + 2)) // 2;
        Tri_down = 0;
        Tri_down = ((N - 2 * K + 1) *(N - 2 * K + 2)) // 2;
        return Tri_up + Tri_down;[/INST]assert No_of_Triangle(4,2) == 7
assert No_of_Triangle(4,3) == 3
assert No_of_Triangle(1,3) == -1</s>