Nastya Is Buying Lunch

Description:

Input:

The first line contains two integers $$$n$$$ and $$$m$$$ ($$$1 \leq n \leq 3 \cdot 10^{5}$$$, $$$0 \leq m \leq 5 \cdot 10^{5}$$$) — the number of pupils in the queue and number of pairs of pupils such that the first one agrees to change places with the second one if the first is directly in front of the second.

The second line contains $$$n$$$ integers $$$p_1$$$, $$$p_2$$$, ..., $$$p_n$$$ — the initial arrangement of pupils in the queue, from the queue start to its end ($$$1 \leq p_i \leq n$$$, $$$p$$$ is a permutation of integers from $$$1$$$ to $$$n$$$). In other words, $$$p_i$$$ is the number of the pupil who stands on the $$$i$$$-th position in the queue.

The $$$i$$$-th of the following $$$m$$$ lines contains two integers $$$u_i$$$, $$$v_i$$$ ($$$1 \leq u_i, v_i \leq n, u_i \neq v_i$$$), denoting that the pupil with number $$$u_i$$$ agrees to change places with the pupil with number $$$v_i$$$ if $$$u_i$$$ is directly in front of $$$v_i$$$. It is guaranteed that if $$$i \neq j$$$, than $$$v_i \neq v_j$$$ or $$$u_i \neq u_j$$$. Note that it is possible that in some pairs both pupils agree to change places with each other.

Nastya is the last person in the queue, i.e. the pupil with number $$$p_n$$$.

Output:

Print a single integer — the number of places in queue she can move forward.

Sample Input:

2 1
1 2
1 2

Sample Output:

1

Sample Input:

3 3
3 1 2
1 2
3 1
3 2

Sample Output:

2

Sample Input:

5 2
3 1 5 4 2
5 2
5 4

Sample Output:

1

Note:

In the first example Nastya can just change places with the first pupil in the queue.

Optimal sequence of changes in the second example is

• change places for pupils with numbers $$$1$$$ and $$$3$$$.
• change places for pupils with numbers $$$3$$$ and $$$2$$$.
• change places for pupils with numbers $$$1$$$ and $$$2$$$.

The queue looks like $$$[3, 1, 2]$$$, then $$$[1, 3, 2]$$$, then $$$[1, 2, 3]$$$, and finally $$$[2, 1, 3]$$$ after these operations.