def count_duplicates(t):
    """
    Count the number of duplicate sets in a given list (t). Return an integer value.
    Sets greater than two are considered a single duplicate set.
    """
    tmp = t[:]
    tmp.sort()
    count = 0
    for i in range(len(t) - 1):
        if tmp[i] == tmp[i + 1] and tmp[i] != tmp[i - 1]:
            count += 1
    return count