def szyfr(s):
t=""
for i in range(0, len(s)-1,2):
t=t+s[i+1]+s[i]
if len(s)%2!=0:
t=t+s[len(s)-1]
return t
print(szyfr("kotwica"))
ZGVmIHN6eWZyKHMpOgoJdD0iIgoJZm9yIGkgaW4gcmFuZ2UoMCwgbGVuKHMpLTEsMik6CgkJCXQ9dCtzW2krMV0rc1tpXQoJaWYgbGVuKHMpJTIhPTA6CgkJCXQ9dCtzW2xlbihzKS0xXQoJcmV0dXJuIHQgCgkJCnByaW50KHN6eWZyKCJrb3R3aWNhIikp