def countNumber(arr):

    memory = {}
    for n,m in arr:
        c = 0

        for number in range(n, m + 1):

            if number not in memory:
                is_equal = len(set(str(number))) == len(str(number))
                if is_equal:
                    memory[number] = is_equal
                    c += 1
            else:
                if memory[number]:
                    c += 1


        print(c)

countNumber([[1,20], [9,19]])