1 //15MS    376K    695 B    C++    
 2 #include<stdio.h>
 3 #include<math.h>
 4 #define N 1000005
 5 struct node{
 6     double x,y; 
 7 }p[N];
 8 double getsum(node a,node b,node c)
 9 {
10     return ((b.x-a.x)*(c.y-a.y)-(c.x-a.x)*(b.y-a.y))/2.0;
11 }
12 int main(void)
13 {
14     int t,n;
15     scanf("%d",&t);
16     while(t--)
17     {
18         scanf("%d",&n);
19         for(int i=0;i<n;i++)
20             scanf("%lf%lf",&p[i].x,&p[i].y);
21         double ss=0,sx=0,sy=0;
22         for(int i=0;i<n-2;i++){
23             double ts=getsum(p[0],p[i+1],p[i+2]);
24             ss+=ts;
25             sx+=ts*(p[0].x+p[i+1].x+p[i+2].x);
26             sy+=ts*(p[0].y+p[i+1].y+p[i+2].y);
27         }
28         printf("%.2lf %.2lf\n",sx/ss/3,sy/ss/3);
29     }
30     return 0;
31 }