S_in = input()
S_out = ""
for s in S_in:
    if ord(s) >= 65 and ord(s) <= 92:
        S_out += chr(ord(s) + 32)
    elif ord(s) >= 97 and ord(s) <= 122:
        S_out += chr(ord(s) - 32)
print(S_out)