from typing import Counter


def jaccard_repeats(a, b):
    """Jaccard similarity measure between input iterables,
    allowing repeated elements"""
    _a = Counter(a)
    _b = Counter(b)
    c = (_a - _b) + (_b - _a)
    n = sum(c.values())
    return 1 - n/(len(a) + len(b) - n)