CF1203F1.Complete the Projects (easy version)

The only difference between easy and hard versions is that you should complete all the projects in easy version but this is not necessary in hard version.

Polycarp is a very famous freelancer. His current rating is $r$ units.

Some very rich customers asked him to complete some projects for their companies. To complete the $i$-th project, Polycarp needs to have at least $a_i$ units of rating; after he completes this project, his rating will change by $b_i$ (his rating will increase or decrease by $b_i$) ($b_i$ can be positive or negative). Polycarp's rating should not fall below zero because then people won't trust such a low rated freelancer.

Is it possible to complete all the projects? Formally, write a program to check if such an order of the projects exists, that Polycarp has enough rating before starting each project, and he has non-negative rating after completing each project.

In other words, you have to check that there exists such an order of projects in which Polycarp will complete them, so he has enough rating before starting each project, and has non-negative rating after completing each project.

简单版本与困难版本的唯一区别在于：在简单版本中，你需要完成所有项目；而在困难版本中，这并非必需。

Polycarp 是一位非常著名的自由职业者，他当前的评分为 $r$ 单位。

一些非常富有的客户邀请他为他们的公司完成若干项目。要完成第 $i$ 个项目，Polycarp 的评分至少需达到 $a_i$ 单位；完成该项目后，他的评分将变化 $b_i$（即评分增加或减少 $b_i$ 单位）（$b_i$ 可为正数或负数）。Polycarp 的评分不能低于零，否则人们将不再信任如此低评分的自由职业者。

是否可能完成所有项目？形式化地说，请编写一个程序，判断是否存在一种项目执行顺序，使得 Polycarp 在开始每个项目前均具有足够的评分，并且在完成每个项目后其评分仍为非负数。

换言之，你需要判断是否存在一种项目执行顺序，使得 Polycarp 在开始每个项目前均有足够评分，并且在完成每个项目后其评分均保持非负。

The first line of the input contains two integers $n$ and $r$ ($1 \le n \le 100, 1 \le r \le 30000$) — the number of projects and the initial rating of Polycarp, respectively.

The next $n$ lines contain projects, one per line. The $i$-th project is represented as a pair of integers $a_i$ and $b_i$ ($1 \le a_i \le 30000$, $-300 \le b_i \le 300$) — the rating required to complete the $i$-th project and the rating change after the project completion.

输入的第一行包含两个整数 $n$ 和 $r$（$1 \le n \le 100$，$1 \le r \le 30000$），分别表示项目的数量和 Polycarp 的初始评分。

接下来的 $n$ 行每行描述一个项目。第 $i$ 个项目由一对整数 $a_i$ 和 $b_i$（$1 \le a_i \le 30000$，$-300 \le b_i \le 300$）表示，其中 $a_i$ 是完成第 $i$ 个项目所需的最低评分，$b_i$ 是完成该项目后评分的变化量。

Print "YES" or "NO".

输出 "YES" 或 "NO"。

In the first example, the possible order is: $1, 2, 3$.

In the second example, the possible order is: $2, 3, 1$.

In the third example, the possible order is: $3, 1, 4, 2$.

在第一个例子中，可能的顺序是：$1, 2, 3$。

在第二个例子中，可能的顺序是：$2, 3, 1$。

在第三个例子中，可能的顺序是：$3, 1, 4, 2$。