#Python - 44 70

Updated for OP's changes.

I'm a Python newbie, so any critique is welcome.

print("".join(chr(ord(c)+32) if 64<ord(c)<91 else c for c in input()))

Python 3 - 70

Updated for OP's changes.

I'm a Python newbie, so any critique is welcome.

print("".join(chr(ord(c)+32) if 64<ord(c)<91 else c for c in input()))

#Python - 44

I'm a Python newbie, so any critique is welcome. Also, not sure if using the character's lower() is disallowed, since it's not by the rules. (It says only the string's lower() is.)

print("".join(c.lower() for c in input("")))

If that is disallowed, then here's a 49 character version:

print("".join(chr(ord(c)+32) for c in input("")))

#Python - 44 70

Updated for OP's changes.

I'm a Python newbie, so any critique is welcome.

print("".join(chr(ord(c)+32) if 64<ord(c)<91 else c for c in input()))

#Python - 44

I'm a Python newbie, so any critique is welcome, haha. Also, not sure if using the character's lower() is disallowed, since it's not by the rules. (It says only the string's lower() is.)

print("".join(c.lower() for c in input("")))

If that is disallowed, then here's a 49 character version:

print("".join(chr(ord(c)+32) for c in input("")))

#Python - 44

I'm a Python newbie, so any critique is welcome. Also, not sure if using the character's lower() is disallowed, since it's not by the rules. (It says only the string's lower() is.)

print("".join(c.lower() for c in input("")))

If that is disallowed, then here's a 49 character version:

print("".join(chr(ord(c)+32) for c in input("")))