Two Logical Flags

Source: Phước Hưng OJ

Version: Phuoc Hung OJ Extended

Problem Statement

Given two integers $a$ and $b$ used as logical flags under C semantics: nonzero means true and zero means false. Determine whether both flags are true.

Input

A single line contains two integers $a$ and $b$.

Output

Print YES if $a e0$ and $b e0$; otherwise print NO.

Subtasks

• Subtask 1 (20 points): $-2\le a,b\le 2$.
• Subtask 2 (30 points): $-100\le a,b\le 100$.
• Subtask 3 (50 points): $-1000\le a,b\le 1000$.

Examples

Example 1

Input

-2 3

Output

YES

Explanation

The flags are a = -2 and b = 3. A flag is true exactly when it is nonzero. Evaluating both flags gives the result YES.

Example 2

Input

0 7

Output

NO

Explanation

The flags are a = 0 and b = 7. A flag is true exactly when it is nonzero. Evaluating both flags gives the result NO.