#include<iostream>
using namespace std;
#define M 10000
#define N 1000000
int m , n;
int str[N];
int cmp[M] , next[M];
void InitNext()
{
int j , k;
next[0] = -1;
j = -1;
k = 0;
while( k < m )
{
if( j == -1 )
{ ++k; ++j; next[k] = j; }
if( cmp[k] == cmp[j] )
{ ++k; ++j; next[k] = j; }
else
{ j = next[j]; }
}
}
int IndexKMP()
{
int i , j;
i = 0;
j = 0;
while( i < n && j < m )
{
if( j == -1 )
{ ++j; ++i; }
if( cmp[j] == str[i] )
{ ++j; ++i; }
else
{ j = next[j]; }
}
if( j == m )
{ return i - j; }
else
{ return -2; }
}
int main()
{
int t;
int i;
scanf( "%d" , &t );
while( t-- )
{
scanf( "%d %d" , &n , &m );
for( i = 0 ; i < n ; ++i )
{ scanf( "%d" , &str[i] ); }
for( i = 0 ; i < m ; ++i )
{ scanf( "%d" , &cmp[i] ); }
InitNext();
printf( "%d/n" , IndexKMP() + 1 );
}
return 0;
}