Jelly Flavours

Amy is a big fan of jelly, and wishes to buy some for dessert. There are a total of $n$ flavours of jelly, numbered $0$ to $n-1$. Store A sells jelly of flavour $i$ for $a\[i]$ dollars a piece, whereas Store B sells it for $b\[i]$ dollars a piece. Amy can spend up to $x$ dollars in Store A and up to $y$ dollars in Store B.

Help Amy find the maximum number of unique flavours of jelly she can purchase.

• $1 \leq n \leq 2000$
• $0 \leq x, y \leq 10\\;000$
• $0 \leq a\[i], b\[i] \leq 10\\;000$ (for all $0 \leq i \leq n-1$)