Write a program that prints the maximum element of a square matrix below the main diagonal. The elements of the main diagonal are also taken into account.

def max(matrix):
  n = len(matrix)
  max_element = matrix[0][0]
  for i in range(n):
    for j in range(n):
      if i > j:
        if matrix[i][j] > max_element:
          max_element = matrix[i][j]
  return max_element
        
matrix = [[1, -2, 3], [4, -5, 6], [7, -8, 9]]
print(max(matrix))