#include<bits/stdc++.h>
#define IL inline
#define reg register
#define N 100100
IL int read()
{
    reg int x=0; reg char ch=getchar();
    while(ch<'0'||ch>'9')ch=getchar();
    while(ch>='0'&&ch<='9')x=x*10+ch-'0',ch=getchar();
    return x;
}

int n,m,a[N][2][3],mx[3];

struct Node
{
    int p,c,w;
    IL bool operator <(const Node &a)const{return w>a.w;}
};

bool type[N];
int ans=1e9;

IL void cmin(reg int &x,reg int y){x>y?x=y:0;}
IL void cmax(reg int &x,reg int y){x<y?x=y:0;}

IL void work()
{
    n=read(),memset(mx,0,sizeof(mx));
    for(reg int i=1;i<=n;++i)type[i]=0;
    std::priority_queue<Node>q[3];
    for(reg int i=1,j,k;i<=n;++i)
    {
        for(j=0;j<2;++j)for(k=0;k<3;++k)a[i][j][k]=read();
        for(j=3;j--;)cmax(mx[j],a[i][0][j]),q[j].push({i,0,a[i][0][j]});
    }
    ans=1e9;
    while(1)
    {
        reg int id,w=-1,p;
        for(reg int o=3,val;o--;)
        {
            while(!q[o].top().c&&type[q[o].top().p])q[o].pop();
            val=mx[o]-q[o].top().w; if(w<val)w=val,id=o;
        }
        cmin(ans,w); if(type[p=q[id].top().p])break; type[p]=1;
        for(reg int o=3;o--;)q[o].push({p,1,a[p][1][o]}),cmax(mx[o],a[p][1][o]);
    }
    printf("%d\n",ans);

}

main()
{
    for(reg int t=read();t--;work());
}