def test_solution_3():
sol = Solution()
x = [1, 3, 2, 3, 5, 0]
result = sol.count_elements(x)
assert result == 3
def test_solution_1():
sol = Solution()
x = [1, 2, 3]
result = sol.count_elements(x)
assert result == 2
def test_solution_2():
sol = Solution()
x = [1, 1, 3, 3, 5, 5, 7, 7]
result = sol.count_elements(x)
assert result == 0
