Two Waves - Repovive Starter Round 2 | Repovive

10A. Two Waves

500 pts1s256 MB

There is an infinite tape of cells numbered $0, 1, 2, \ldots$ .

Two waves start at time $0$ . The first wave starts from cell $a$ , and the second wave starts from cell $b$ .

A wave reaches a neighboring cell in exactly $1$ second. More formally, the wave starting from cell $x$ reaches cell $y$ at time $|x-y|$ .

Determine whether there exists a cell $c$ such that both waves reach cell $c$ at the same time.

a \quad b

Print Yes if there exists such a cell. Otherwise, print No.

Input

2 6

Explanation

Both waves reach cell 4 at time 2.

Output

Yes

Input

3 8

Explanation

There is no cell whose distance from 3 is equal to its distance from 8.

Output

No

Input

0 0

Explanation

Both waves start from cell 0, so they reach cell 0 at time 0.

Output

Yes

There is an infinite tape of cells numbered $0, 1, 2, \ldots$ .

Two waves start at time $0$ . The first wave starts from cell $a$ , and the second wave starts from cell $b$ .

A wave reaches a neighboring cell in exactly $1$ second. More formally, the wave starting from cell $x$ reaches cell $y$ at time $|x-y|$ .

Determine whether there exists a cell $c$ such that both waves reach cell $c$ at the same time.

a \quad b