#P1167. Draw Grids

Draw Grids

Background

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Description

ZYT and LBC decided to play a game.

They will alternately do the following operation.

  • Pick 4 integers a,b,c,d(1a,cna,b,c,d(1\leq a,c \leq n andand 1b,dm) 1b,dm) 1≤b,d≤m)\ 1\leq b,d \leq m), where ac+bd=1{ |a-c|+|b-d|=1} , and draw a straight segment between point (a,b){(a,b)} and point(c,d){(c,d)}. The segment shouldn't overlap with a segment that already exists.
  • In any time, the segments shouldn't form a polygon. That is, there exists no sequence of distinct points(x0,y0),(x1,y1),,(xk1,yk1) {(x_0,y_0),(x_1,y_1),⋯,(x_{k−1},y_{k−1})} satisfying for each integer u<k \leq u < k,there is a segment between(xu,yu)(x_u,y_u) and $(x_{ (u+1)\ \text{mod}\ k },y_{ (u+1)\ \text{mod}\ k })$.

The player who can't perform an operation during his move loses.

Determine whether ZYT can win considering that both players play optimally and ZYT starts. img img

Format

Input

The input consists of one line containing two integers n{n}n and m{m}m.

Output

Print "YES"(without quote) if ZYT can win and "NO"(without quote) if ZYT can't.

Samples

1 3
NO
2 2
YES

Limitation

1s, 1024KiB for each test case.

It is guaranteed that 1n,m4 1\le n,m\le 4.