we can use the simple swapcase function to do it

def swap_case(s):

return s.swapcase()

if name == 'main': s = input() result = swap_case(s) print(result)

def swap_case(s): result = "" for i in s: if i.islower(): result += i.upper() elif i.isupper(): result += i.lower() else: result += i return result

For Python3

def swap_case(s):
    return s.swapcase()
 
if __name__ == '__main__':
    s = input()
    result = swap_case(s)
    print(result)

new_str = "" for char in s: if not char.isalpha(): new_str += char elif char.isupper(): new_str += char.lower() elif char.islower(): new_str += char.upper() return new_str