【Description】

【题目描述】

Given two sequences of numbers : a[1], a[2], ...... , a[N], and b[1], b[2], ...... , b[M] (1 <= M <= 10000, 1 <= N <= 1000000). Your task is to find a number K which make a[K] = b[1], a[K + 1] = b[2], ...... , a[K + M - 1] = b[M]. If there are more than one K exist, output the smallest one.

给定两串数组 : a[1], a[2], ...... , a[N], 和 b[1], b[2], ...... , b[M] (1 <= N <= 1000000, 1 <= M <= 10000)。你的任务是找到一个数字K使得a[K] = b[1], a[K + 1] = b[2], ...... , a[K + M - 1] = b[M]。如果存在多个K, 输出最小的那个。

【Input】

【输入】

The first line of input is a number T which indicate the number of cases. Each case contains three lines.

The first line is two numbers N and M (1 <= M <= 10000, 1 <= N <= 1000000).

The second line contains N integers which indicate a[1], a[2], ...... , a[N].

The third line contains M integers which indicate b[1], b[2], ...... , b[M].

All integers are in the range of [-1000000, 1000000].

输入的第一行是一个数字T 表示测试用例的数量。每个测试用例有三行。

第一行神两个数N和M (1 <= M <= 10000, 1 <= N <= 1000000)。

第二行有N个整数a[1], a[2], ...... , a[N]。

第三行有M个整数b[1], b[2], ...... , b[M]。

所有整数的范围都在 [-1000000, 1000000]。

【Output】

【输出】

For each test case, you should output one line which only contain K described above. If no such K exists, output -1 instead.

对于每个测试用例，输出一行上述K值。如果K不存在，则输出-1.

【Sample Input - 输入样例】

【Sample Output - 输出样例】

2

13 5

1 2 1 2 3 1 2 3 1 3 2 1 2

1 2 3 1 3

13 5

1 2 1 2 3 1 2 3 1 3 2 1 2

1 2 3 2 1

6

-1