#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<iostream>
#include<algorithm>
#define N 20
#define ll long long
using namespace std;
int t,n,a[N],ans;
ll s,q,m[N],tot,w,m1;
ll read()
{
    ll x=0,f=1; char ch=getchar();
    while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘)f=-1; ch=getchar();}
    while(ch>=‘0‘&&ch<=‘9‘){x=x*10+ch-‘0‘; ch=getchar();}
    return x*f;
}
ll exgcd(int a,int b,int &x,int &y)
{
    if(b==0) 
    {
        x=1,y=0;
        return a;
    }
    int r=exgcd(b,a%b,x,y),tmp;
    tmp=x,x=y,y=tmp-a/b*y;
    return r;
 } 
 int crt()
 {
     int a1=a[1],a2,m2,c,d;m1=m[1];
     for(int i=2;i<=n;++i)
     {
         int x=0,y=0;
         a2=a[i],m2=m[i];
         c=a2-a1;
         d=exgcd(m1,m2,x,y);
         int mod=m2/d;
         if(c%d) return -1;
         x=x*c/d;
         x=(x%mod+mod)%mod;
         a1+=m1*x; m1*=mod;
     }
     if(a1==0) a1+=m1;
     return a1;
 }
int main()
{
    t=read();
    while(t--)
    {
        q=read(),n=read();ans=0;
        for(int i=1;i<=n;i++) m[i]=read();
        for(int i=1;i<=n;i++) a[i]=read();
        w=crt();if(w==-1||w>q) printf("0\n");
        else
        {
            ans=1;
            while(w+m1<=q) w+=m1,ans++;
            printf("%d\n",ans);
        }
    }
    return 0;
}