Score : $300$ points

问题描述

高桥站在数轴上的坐标 $0$ 处。

他现在将进行 $N$ 次跳跃。在第 $i$ 次跳跃中 $(1 \leq i \leq N)$，他会向正方向移动 $a_i$ 或者 $b_i$。

请问，在经过 $N$ 次跳跃后，他能否到达坐标 $X$？

以上为通义千问 qwen-max 翻译，仅供参考。

Problem Statement

Takahashi is standing at the coordinate $0$ on a number line.

He will now perform $N$ jumps. In the $i$-th jump $(1 \leq i \leq N)$, he moves $a_i$ or $b_i$ in the positive direction.

Is it possible for him to be at the coordinate $X$ after $N$ jumps?

Constraints

• $1 \leq N \leq 100$
• $1 \leq a_i \lt b_i \leq 100 \, (1 \leq i \leq N)$
• $1 \leq X \leq 10000$
• All values in input are integers.

Input

Input is given from Standard Input in the following format:

$N$ $X$

$a_1$ $b_1$

$\vdots$

$a_N$ $b_N$

Output

If it is possible for Takahashi to be at the coordinate $X$ after $N$ jumps, print Yes; otherwise, print No.

Sample Input 1

2 10
3 6
4 5

Sample Output 1

Yes

By moving $b_1 (= 6)$ in the first jump and $a_2 (= 4)$ in the second jump, he can be at the coordinate $X (= 10)$.

Sample Input 2

2 10
10 100
10 100

Sample Output 2

No

He can be at the coordinate $X (= 10)$ after the first jump, but not after all jumps.

Sample Input 3

4 12
1 8
5 7
3 4
2 6

Sample Output 3

Yes

update @ 2024/3/10 10:20:37