# written for python 3
import os

def check_balance(characters):
    '''Return -1 if all delimiters are balanced or return
       the char number of the first mismatched delimiter.

    '''
    openers = {'(': ')', '{': '}', '[': ']', '“': '”', '‹': '›', '«': '»',
           '【': '】', '〈': '〉', '《': '》', '「': '」', '『': '』'}
    closers = set(openers.values())
    stack = []
    for i, c in enumerate(characters, start=1):
        if c in openers:
            stack.append(openers[c])
        elif c in closers:
            if not stack or c != stack.pop():
                return i
    return -1

def scan(directory, encoding='utf-8'):
    for dirpath, dirnames, filenames in os.walk(directory):
        for filename in filenames:
            fullname = os.path.join(dirpath, filename)
            with open(fullname, 'r', encoding=encoding) as f:
                try:
                    characters = f.read()
                except UnicodeDecodeError:
                    continue
            position = check_balance(characters)
            if position >= 0:
                print('{0!r}: {1}'.format(position, fullname))

scan('.')