Nested Looping

start = input()
end = input()
without = input()
letter_counter = 0
for x1 in range(ord(start), ord(end) + 1):
    for x2 in range(ord(start), ord(end) + 1):
        for x3 in range(ord(start), ord(end) + 1):
            if chr(x1) != without and chr(x2) != without and chr(x3) != without:
                letter_counter += 1
                print(f"{chr(x1)}{chr(x2)}{chr(x3)}", end=" ")
print(letter_counter)