Codeforces Round 461 (Div. 2)
A
Cloning Toys
Codeforces
1300
原题
←B →
翻译中…

Imp likes his plush toy a lot.

翻译中…

image

翻译中…

Recently, he found a machine that can clone plush toys. Imp knows that if he applies the machine to an original toy, he additionally gets one more original toy and one copy, and if he applies the machine to a copied toy, he gets two additional copies.

翻译中…

Initially, Imp has only one original toy. He wants to know if it is possible to use machine to get exactly $*x*$ copied toys and $*y*$ original toys? He can't throw toys away, and he can't apply the machine to a copy if he doesn't currently have any copies.

翻译中…

Input

翻译中…

The only line contains two integers $*x*$ and $*y*$ ($0 ≤ *x*, *y* ≤ 10^{9}$) — the number of copies and the number of original toys Imp wants to get (including the initial one).

翻译中…

Output

翻译中…

Print "Yes", if the desired configuration is possible, and "No" otherwise.

翻译中…

You can print each letter in arbitrary case (upper or lower).

翻译中…

Note

翻译中…

In the first example, Imp has to apply the machine twice to original toys and then twice to copies.

翻译中…

样例

Input #1
6 3
Output #1
Yes
InputCopy OutputCopy
Input #2
4 2
Output #2
No
InputCopy OutputCopy
Input #3
1000 1001
Output #3
Yes
InputCopy OutputCopy
题目信息
题号
922A
时间限制
1 s
内存限制
256 MB
标签
模拟

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。