1 #include<cstring>
 2 #include<cstdio>
 3 #include<map>
 4 #include<iostream>
 5 using namespace std;
 6 map<int,int>M;
 7 int nex[10005],l1,l2,sl;
 8 int S[1000005],T[10005];
 9 int solve()
10 {
11     int i,j;
12     nex[0]=nex[1]=0;
13     for(i=1;i<l2;++i)
14     {
15         j=nex[i];
16         while(j&&T[i]!=T[j])j=nex[j];
17         nex[i+1]=T[i]==T[j]?j+1:0;
18     }
19     j=0;
20     for(i=0;i<l1;++i)
21     {
22         while(j&&S[i]!=T[j])j=nex[j];
23         if(S[i]==T[j]){
24             j++;
25             if(j==l2)return i-l2+2;
26         }
27     }
28     return -1;
29 }
30 int main()
31 {
32     int i,j,t,p,x,tmp;
33     cin>>t;
34     while(t--){p=0;M.clear();
35         scanf("%d%d",&l1,&l2);
36         for(i=0;i<l1;++i)
37         {
38             scanf("%d",&x);
39             tmp=M[x];
40             if(!tmp){M[x]=S[i]=++p;}
41             else S[i]=tmp;
42         }
43         for(i=0;i<l2;++i)
44         {
45             scanf("%d",&x);
46             tmp=M[x];
47             if(!tmp){M[x]=T[i]=++p;}
48             else T[i]=tmp;
49         }
50         cout<<solve()<<endl;;
51     }
52     return 0;
53 }