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def solution(n, lost, reserve):
    new_lost = set(lost) - set(reserve)
    new_reserve = set(reserve) - set(lost)
    for i in new_lost:
        if i - 1 in new_reserve:
            new_reserve.remove(i - 1)
            continue
        elif i + 1 in new_reserve:
            new_reserve.remove(i + 1)
        else:
            n-=1
    return n