Letters Combinations

x = ord(input())
y = ord(input())
z = ord(input())
counter = 0
output = ''

for i in range(x, y + 1):
    for k in range(x, y + 1):
        for j in range(x, y + 1):
            if i != z and k != z and j != z:
                output += f"{chr(i)}{chr(k)}{chr(j)} "
                counter += 1

print(output + str(counter))


Или:

x = ord(input())
y = ord(input())
z = ord(input())
counter = 0

for i in range(x, y + 1):
    for k in range(x, y + 1):
        for j in range(x, y + 1):
            if i != z and k != z and j != z:
                print(chr(i) + chr(k) + chr(j), end=' ')
                counter += 1
print(counter)