def is_paired(input_string):
    stack = []

    for char in input_string:
        if char == '(' or char == '[]' or char == '{':
            stack.append(char)

        else if char == ')':
            if len(stack) == 0 or stack.pop() != '(':
                return False
        else if char == ']':
            if len(stack) == 0 or stack.pop() != '[':
                return False
        else if char == '}':
            if len(stack) == 0 or stack.pop() != '{':
                return False

    return len(stack) == 0