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blaire

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kmp hdu 1711 number sequence

### Description

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

### Input

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, a, …… , a[N]. The third line contains M integers which indicate b, b, …… , b[M]. All integers are in the range of [-1000000, 1000000].

### Output

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

### Sample Input

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