#include <iostream>#include<stdio.h>#include<algorithm>using namespace std;struct point{ int x,y;};point a[100],b[100],c[100],f[100],aa[100];double xmult(point a,point b,point c){ return (a.x-c.x)*(b.y-c.y)-(b.x-c.x)*(a.y-c.y);}bool cmp(point a,point b){ if (a.y<b.y||a.y==b.y&&a.x<b.x) return true; return false;}bool mult(point sp, point ep, point op){return (sp.x - op.x) * (ep.y - op.y)>= (ep.x - op.x) * (sp.y - op.y);}void gram(int n,int flag){ int i,t,p,h; point g; sort(aa,aa+n,cmp); a[0]=aa[0]; p=1; for(i=1;i<n;i++) if(aa[i].x==aa[i-1].x&&aa[i].y==aa[i-1].y) continue; else a[p++]=aa[i]; n=p; b[0]=a[0]; if(n==1) { printf("%d %dn%d %dn",flag,1,b[0].x,b[0].y); return ; } b[1]=a[1]; if (n==2) { if (b[1].y>b[0].y) h=1; else h=0; printf("%d %dn%d %dn%d %dn",flag,2,b[h].x,b[h].y,b[(h+1)%2].x,b[(h+1)%2].y); return ; } b[2]=a[2]; int top=1,len; for (i = 2; i < n; i++) { while (top && mult(a[i], b[top], b[top-1])) top--; b[++top] = a[i]; } len = top; b[++top] = a[n - 2]; for (i = n - 3; i >= 0; i--) { while (top!=len && mult(a[i], b[top], b[top-1])) top--; b[++top] = a[i]; } t=top; f[0]=b[0]; h=1; for(i=0;i<t;i++) f[i]=b[i]; g=b[t-1]; h=t-1; for(i=0;i<t;i++) if (f[i].y>g.y||f[i].y==g.y&&f[i].x<g.x) { h=i; g=f[i]; } for(i=0;i<t;i++) c[i]=f[(i+h)%t]; c[t]=c[0]; printf("%d %dn",flag,t); for(i=t;i>0;i--) printf("%d %dn",c[i].x,c[i].y);}int main() { int ii,tt,flag,n,i; scanf("%d",&tt); for(ii=1;ii<=tt;ii++) { scanf("%d%d",&flag,&n); for(i=0;i<n;i++) scanf("%d%d",&aa[i].x,&aa[i].y); gram(n,flag); } return 0;}
