def test_parens_odd_input():
assert parens(None) == 0
assert parens(1) == 0
assert parens('') == 0
def test_parens():
assert parens('()') == 0
assert parens('()()') == 0
assert parens('((()(())()))') == 0
assert parens('(') == 1
assert parens('(()') == 1
assert parens('(()()') == 1
assert parens(')') == -1
assert parens('()())') == -1
assert parens('((()(())())))') == -1
assert parens('(a tes(t )string)') == 0
assert parens('(awerbw(r)tnw45nwrtn') == 1
assert parens('a(;;,blk)nqw)3po') == -1
