CF1209B.Koala and Lights

It is a holiday season, and Koala is decorating his house with cool lights! He owns $n$ lights, all of which flash periodically.

After taking a quick glance at them, Koala realizes that each of his lights can be described with two parameters $a_i$ and $b_i$. Light with parameters $a_i$ and $b_i$ will toggle (on to off, or off to on) every $a_i$ seconds starting from the $b_i$-th second. In other words, it will toggle at the moments $b_i$, $b_i + a_i$, $b_i + 2 \cdot a_i$ and so on.

You know for each light whether it's initially on or off and its corresponding parameters $a_i$ and $b_i$. Koala is wondering what is the maximum number of lights that will ever be on at the same time. So you need to find that out.

Here is a graphic for the first example.

正值假日季，考拉正在用炫酷的彩灯装饰他的房子！他拥有 $n$ 盏灯，每盏灯均按固定周期闪烁。

经过快速观察，考拉意识到每盏灯均可由两个参数 $a_i$ 和 $b_i$ 描述。参数为 $a_i$ 和 $b_i$ 的灯将从第 $b_i$ 秒起，每隔 $a_i$ 秒切换一次状态（即开→关或关→开）。换言之，它将在时刻 $b_i$、$b_i + a_i$、$b_i + 2 \cdot a_i$ 等时刻切换状态。

你已知每盏灯的初始状态（开或关）及其对应参数 $a_i$ 和 $b_i$。考拉想知道：在任意时刻，最多有多少盏灯同时处于开启状态？因此你需要求出该最大值。

这是第一个样例的示意图。

The first line contains a single integer $n$ ($1 \le n \le 100$), the number of lights.

The next line contains a string $s$ of $n$ characters. The $i$-th character is "1", if the $i$-th lamp is initially on. Otherwise, $i$-th character is "0".

The $i$-th of the following $n$ lines contains two integers $a_i$ and $b_i$ ($1 \le a_i, b_i \le 5$) — the parameters of the $i$-th light.

第一行包含一个整数 $n$（$1 \le n \le 100$），表示灯的数量。

第二行包含一个长度为 $n$ 的字符串 $s$。其中第 $i$ 个字符为 "1" 表示第 $i$ 盏灯初始时是开启的；否则（即为 "0"）表示第 $i$ 盏灯初始时是关闭的。

接下来的 $n$ 行中，第 $i$ 行包含两个整数 $a_i$ 和 $b_i$（$1 \le a_i, b_i \le 5$），表示第 $i$ 盏灯的参数。

Print a single integer — the maximum number of lights that will ever be on at the same time.

输出一个整数——同一时刻最多亮起的灯的数量。

For first example, the lamps' states are shown in the picture above. The largest number of simultaneously on lamps is $2$ (e.g. at the moment $2$).

In the second example, all lights are initially on. So the answer is $4$.

对于第一个例子，灯的状态如上图所示。同时亮着的灯的最大数量为 $2$（例如在时刻 $2$）。

在第二个例子中，所有灯初始时都是亮着的。因此答案是 $4$。