#include <cmath>
#include <stdio.h>
 
using namespace std;
 
int main()
{
    int ile;
    int x1,y1,r1;
    int x2,y2,r2;
    int rw,rm;
    double wynik;
 
    scanf("%d",&ile);
    for(int i=0; i<ile; i++)
    {
        scanf("%d%d%d",&x1,&y1,&r1);
        scanf("%d%d%d",&x2,&y2,&r2);
 
        //przesuniecie ukladu wsp do punktu x1,y1
        x2-=x1;
        y2-=y1;
 
        //wyznaczenie wiekszego kola
        rw=r1;
        rm=r2;
        if(r2>r1)
        {
            rw=r2;
            rm=r1;
        }
 
        //kola maja wspolny srodek
        if(x2==0 && y2==0)
        {
            printf("%.2f\n",2.0*rm);
            continue;
        }
 
        //okregi zachodza na siebie calkowicie
        if(x2*x2+y2*y2<=(rw-rm)*(rw-rm))
        {
            printf("%.2f\n",2.0*rm);
            continue;
        }
 
 
        //okregi maja czesc wspolna
        if(((x2*x2)+(y2*y2)>(rw-rm)*(rw-rm))&&((x2*x2)+(y2*y2)<(rw+rm)*(rw+rm)))
        {
            wynik=rw+rm-sqrt((x2*x2)+(y2*y2));
            printf("%.2f\n",wynik);
            continue;
        }
 
        //okregi leza obok siebie
        if(x2*x2+y2*y2>=(r1+r2)*(r1+r2))
        {
            printf("%.2f\n",0.0);
            continue;
        }
    }
    return 0;
}

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6
3 3 3
3 -1 4
-3 -3 3
-1 2 5
3 3 2
-3 -3 1
5 5 10
13 5 4
10 5 2
5 10 3
0 0 10
1 1 100