Problem Statement

There are $N$ wizards, numbered $1, \\ldots, N$.
Wizard $i$ has a strength of $a_i$ and plans to defeat a monster with a strength of $b_i$.

You can perform the following operation any number of times.

• Increase the strength of any wizard of your choice by $1$.

A pair of Wizard $i$ and Wizard $j$ (let us call this pair $(i, j)$) is said to be good when at least one of the following conditions is satisfied.

• Wizard $i$ has a strength of at least $b_i$ and Wizard $j$ has a strength of at least $b_j$.
• Wizard $i$ has a strength of at least $b_j$ and Wizard $j$ has a strength of at least $b_i$.

Your objective is to make the pair $(x_i, y_i)$ good for every $i=1, \\ldots, M$.
Find the minimum number of operations needed to achieve it.

Constraints

• $2 \\leq N \\leq 100$
• $1 \\leq a_i,b_i \\leq 100$
• $1 \\leq M \\leq \\frac{N(N-1)}{2}$
• $1 \\leq x_i \\lt y_i \\leq N$
• $(x_i,y_i) \\neq (x_j,y_j)$, if $i\\neq j$.
• All values in input are integers.

Input

Input is given from Standard Input in the following format:

$N$ $a_1$ $b_1$ $\\vdots$ $a_N$ $b_N$ $M$ $x_1$ $y_1$ $\\vdots$ $x_M$ $y_M$

Output

Print the answer.

Sample Input 1

5
1 5
2 4
3 3
4 2
5 1
3
1 4
2 5
3 5

Sample Output 1

2

You can perform the operation once for Wizard $1$ and once for Wizard $4$ to achieve the objective with the fewest operations.

Sample Input 2

4
1 1
1 1
1 1
1 1
3
1 2
2 3
3 4

Sample Output 2

0

No operation is needed.

Sample Input 3

9
1 1
2 4
5 5
7 10
9 3
9 13
10 9
3 9
2 9
7
1 5
2 5
1 6
2 4
3 4
4 9
8 9

Sample Output 3

22