#include <iostream>
#include <cstdio>
#include <cmath>
#include <cstring>
#include <algorithm>
#include<map>
using namespace std;
const int N = 315, M = 30005, mod = 1e9 + 7, inf = 0x3f3f3f3f;
typedef long long ll;

int dp[N][N];
ll a[N],d;
map<ll,int > mp;
int dfs(int l,int r) {
    if(dp[l][r]!=-1) return dp[l][r];
    int& ret = dp[l][r];
    ret = 0;
    if(l>=r) return ret;

    if(l+1==r) {
        if(mp[a[r]-a[l]]) return (ret = 2);
        else return (ret = 0);
    }

    int tmp = 0;
    if(mp[a[r]-a[l]]) tmp+=2;
    if(dfs(l+1,r-1)==((r-1)-(l+1)+1)) ret = tmp+((r-1)-(l+1)+1);

    tmp = 0;
    if(a[l+1]-a[l]==a[r]-a[l+1]&&mp[a[r]-a[l+1]]) tmp+=3;
    if(dfs(l+2,r-1) == ((r-1)-(l+2)+1))ret = max(ret,tmp+((r-1)-(l+2)+1));

    tmp = 0;
    if(a[r-1]-a[l]==a[r]-a[r-1]&&mp[a[r]-a[r-1]]) tmp+=3;
    if(dfs(l+1,r-2) == ((r-2)-(l+1)+1)) ret = max(ret,tmp+((r-2)-(l+1)+1));

    for(int i=l+1;i<r;i++) {
        ret = max(ret,dfs(l,i)+dfs(i+1,r));
    }
    return ret;
}
int main() {
    int T,m,n;
    scanf("%d",&T);
    while(T--) {
        mp.clear();
        memset(dp,-1,sizeof(dp));
        scanf("%d%d",&n,&m);
        for(int i=1;i<=n;i++) scanf("%I64d",&a[i]);
        for(int i=1;i<=m;i++) scanf("%I64d",&d),mp[d] = 1;
        printf("%d\n",dfs(1,n));
    }
    return 0;
}