xd = lambda s,k,z=0: ''.join([[[chr(ord(l)+i) if ord(l)+i<=ord('z') else chr(ord(l)+i-26) for i in range(26)] for l in k.lower()][litera[0]%len(k)][[chr(ord('a')+i) if ord('a')+i<=ord('z') else chr(ord('a')+i-26) for i in range(26)].index(litera[1])] for litera in enumerate(s)]) if z else ''.join([chr(ord(x)+k%26) if ord(x)+k%26<=ord('z') else chr(ord(x)+k%26-26) for x in s.lower()])
print(xd('costam','klucz',1))
print(xd('costam',3))