Alec Game

Alec is playing a game with his 3 years old sister. His sister has recently learned lower case English alphabets. She writes the word $X$ in her copy at the same time Alec also writes the word $Y$ in his copy. After that they match the words if the word $Y$ is a subsequence of word $X$ then Alec wins, else he loses. You are given the number of matches they played N, and both the words $X$ and $Y$