Takahashi decided to make takoyaki (octopus balls) and serve it to Snuke. Takahashi instructed Snuke to raise only his left hand if he wants to eat takoyaki, and only his right hand otherwise.

You are given the information about which hand Snuke is raising as two integers $L$ and $R$. He is raising his left hand if and only if $L = 1$, and raising his right hand if and only if $R = 1$. He might not follow the instructions and could raise both hands or not raise any hand at all.

If Snuke is raising only one hand, print Yes if he wants to eat takoyaki, and No if he does not. If he is raising both hands or not raising any hand, print Invalid.

Assume that if Snuke is raising only one hand, he is always following the instructions.

The input is given from Standard Input in the following format:

$L$ $R$

Print Yes, No, or Invalid according to the instructions in the problem statement.

• Each of $L$ and $R$ is $0$ or $1$.