next_or_none = lambda a: next(a, None)
def izip_large(*iterables):
    iterators = map(iter, iterables)
    while iterators:
        next_item = tuple(map(next_or_none, iterators))
        if not any(next_item):
            return
        yield next_item
for i in izip_large('ABCD', 'xy'):
    print i