Point and Square

Problem Description

There is a square whose four corners have coordinates $(x, y)$ equal to $(1,-1), (1,1), (-1,-1), (-1,1)$, where $x$ is the horizontal axis and $y$ is the vertical axis. Write a program to determine whether a given point lies inside this square (including its boundary).

Input Format

A single line containing two integers $x, y$ separated by a space, representing the coordinates $(x, y)$.

Output Format

A single line: if the point is inside the square, output yes; otherwise output no.

Sample Input

1 1

Sample Output

yes

Hint

• The square's boundary is $-1 \le x \le 1$ and $-1 \le y \le 1$.
• The statement says including the boundary — think about whether to use >= / <= or > / <.
• Check against the sample: $(1, 1)$ lies exactly on a corner, so output yes.