#include<iostream>
using namespace std;


int n = 0, m = 0;
int FindAncestor(int* post, int* in, int a, int b, int size)
{
	int root = post[size - 1];
	if (root == a || root == b)
		return root;

	//中序遍历根的下标
	int rooti;
	for (rooti = 0; rooti < size; rooti++)
	{
		if (root == in[rooti])
			break;
	}

	//找到a,b在中序遍历的下标
	int p = 0, q = 0;
	for (int i = 0; i < n; i++)
	{
		if (a == in[i])
			p = i;
		if (b == in[i])
			q = i;
	}
	if (p < rooti && q < rooti) 
	{
		FindAncestor(post, in, a, b, rooti);
	}
	else if (p > rooti && q > rooti) 
	{
		FindAncestor(post + rooti, in + rooti + 1, a, b, size - rooti - 1);
	}
	else 
		return in[rooti];
}
bool IsInTree(int* arr, int n, int x)
{
	for (int i = 0; i < n; i++)
	{
		if (x == arr[i])
			return true;
	}
	return false;
}
int main()
{
	cin >> n >> m;

	int in[10000] = { 0 };
	int post[10000] = { 0 };
	for (int i = 0; i < n; i++)
		cin >> post[i];
	for (int i = 0; i < n; i++)
		cin >> in[i];

	while (m--)
	{
		int a, b;
		cin >> a >> b;
		if (!IsInTree(post, n, a) || !IsInTree(post, n, b))
		{
			cout << "ERROR" << endl;
			continue;
		}
		cout << FindAncestor(post, in, a, b, n) << endl;
	}

	return 0;
}