题目描述
Problem Background

Little A has recently become obsessed with the game "Jump Jump".
Problem Description
The rules of "Jump Jump" that Little A plays are as follows:
- Set a counter $\text{cnt}$ with an initial value of $2$.
- If you jump to the next square but do not land on its center, add $1$ point and reset $\text{cnt}$ to $2$.
- If you jump to the next square and land on its center, add $\text{cnt}$ points and double $\text{cnt}$.
- If the next square is a special square $x_i$ and you land on its center, add an additional $y_i$ points.
- The termination condition is either failing to jump to the next square or completing all the squares.
Given that there are $n$ squares, numbered from $1$ to $n$ (excluding the starting square).
The probability that Little A jumps to the next square but does not land on its center is $a\%$, the probability that he jumps to the next square and lands on its center is $b\%$, and the remaining $(100-a-b)\%$ is the probability of failing to jump to the next square.
Calculate his expected score modulo $10^9+7$.
Input Format
The first line contains three integers $n, a, b$.
The second line contains an integer $m$, representing the number of special squares.
The next $m$ lines each contain two integers $x, y$, representing the number of each special square and its additional points, ensuring that $x$ is unique.
Output Format
An integer representing the expected score.
Sample Input and Output
Input Sample #1
3 0 100
0
Output Sample #1
14
Input Sample #2
3 100 0
0
Output Sample #2
3
Input Sample #3
3 0 0
0
Output Sample #3
0
Input Sample #4
3 0 100
3
1 10
2 10
3 10
Output Sample #4
44
Input Sample #5
114 5 14
3
14 15
92 65
100 100
Output Sample #5
190259152
Notes
[Sample 1 Explanation]
Little A always jumps to the next square and lands on its center, the expected score is $2+4+8=14$ points.
[Sample 2 Explanation]
Little A always jumps to the next square but does not land on its center, the expected score is $1+1+1=3$ points.
[Sample 3 Explanation]
Little A cannot jump to the next square, the expected score is $0$ points.
[Sample 4 Explanation]
Little A always jumps to the next square and lands on its center, the expected score is $2+10+4+10+8+10=44$ points.
[Data Range and Constraints]
This problem uses bundled testing.
The table below indicates no special restrictions where a slash is used.
| Subtask | Points | $n$ | $a$ | $b$ | $m$ |
|---|---|---|---|---|---|
| $1$ | $1$ | $=1$ | $=50$ | $=50$ | / |
| $2$ | $9$ | $\le 20$ | / | / | $=0$ |
| $3$ | $10$ | $\le 20$ | / | / | / |
| $4$ | $10$ | $\le 10^5$ | / | / | $=0$ |
| $5$ | $20$ | $\le 10^5$ | / | / | / |
| $6$ | $5$ | / | $=0$ | $=100$ | / |
| $7$ | $5$ | / | $=100$ | $=0$ | / |
| $8$ | $15$ | / | / | / | $=0$ |
| $9$ | $25$ | / | / | / | / |
For $100\%$ of the data, $1\le n\le 10^{18}$, $0\le a,b,a+b\le 100$, $0\le m\le \min(n,10^5)$, $1\le x\le n$, $1\le y\le 100$.
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分