The longest word is over 99 times longer and it's existence as a real world is disputed. It's obviously too long to post here, so here's a clip of it being pronounced:
let's say we have a string containing only x and y of length n. Ex. if n = 5, a valid string would be xxxyx, which contains 1 (or odd number of) y prove that the number of possibilities of a valid string of length n containing an even number of 'y's is equal to the number of possibilities of a valid string of length n containing an odd number of 'y's