Marisa has a garden with $n$ plots, and each plot $i$ initially contains $A_i$ units of soil. Marisa wants to modify the amount of soil in each plot so that they contain $B_i$ units of soil.
Marisa can perform the following actions, each with its associated cost:
- Buy an additional unit of soil at a cost of $x$.
- Dump a unit of soil from a plot at a cost of $y$.
- Move an unit of soil from plot $i$ to plot $j$ at a cost of $|i-j| \times z$.
Your task is to determine the minimum cost for Marisa to renovate her garden by adjusting the soil in each plot.
### Input
- The first line contains four integers $n,x,y,z$.
- The next $n$ lines, each line contains two integers $A_i,B_i$.
### Output
- Print an integer, the minimum cost.
### Constraints
- $1 \le n \le 500$.
- $1 \le x, y, z \le 1000$.
- $0 \le A_i, B_i \le 10$.
### Example
Input:
```
4 100 200 1
1 4
2 3
3 2
4 0
```
Output:
```
210
```
