def swap_case(s):
    my_list = []
    for i in s:
        if 65 <= ord(i) <= 90:
            i = chr(ord(i) + 32)
            my_list.append(i)
        elif 97 <= ord(i) <= 122:
            i = chr(ord(i) - 32)
            my_list.append(i)
        else:
            my_list.append(i)
    return ''.join(my_list)

if __name__ == '__main__':
    s = input()
    result = swap_case(s)
    print(result)