s = "((([]){}))"

stack = []
good = True
for c in s:
    if c in '[{(':
        stack.append(c)
    elif c in ')}]':
        if not stack:
            good = False
            break
        opening = stack.pop()
        if opening + c not in ['()', '[]', '{}']:
            good = False
            break
if stack:
    good = False

print(s, 'is', good)