/* 3285 */

 #include <iostream>

 #include <cstdio>

 #include <cstring>

 #include <cmath>

 #include <algorithm>

 using namespace std;

 #define MAXN 55

 typedef struct {

     int x, y;

 } Point_t;

 Point_t points[MAXN];

 Point_t stack[MAXN];

 int top;

 void output(int);

 double dist(Point_t a, Point_t b) {

     return sqrt(1.0*(a.x-b.x)*(a.x-b.x) + (a.y-b.y)*(a.y-b.y));

 }

 int dist2(Point_t a, Point_t b) {

     return (a.x-b.x)*(a.x-b.x) + (a.y-b.y)*(a.y-b.y);

 }

 int cross(Point_t a, Point_t b, Point_t c) {

     return (b.x-a.x)*(c.y-a.y) - (c.x-a.x)*(b.y-a.y);

 }

 bool comp(Point_t a, Point_t b) {

     int m = cross(points[], a, b);

     return m> || (m== && dist2(points[], a)<dist2(points[], b));

 }

 void Graham(int n) {

     Point_t p;

     int i, j, k;

     p = points[];

     k = ;

     for (i=; i<n; ++i) {

         if (points[i].x<p.x || (points[i].x==p.x && points[i].y<p.y)) {

             p = points[i];

             k = i;

         }

     }

     points[k] = points[];

     points[] = p;

     sort(points+, points+n, comp);

     stack[] = points[];

     stack[] = points[];

     top = ;

     for (i=; i<n; ++i) {

         while(top && cross(stack[top-], stack[top], points[i])<=)

             --top;

         stack[++top] = points[i];

     }

 }

 int main() {

     int t, case_n;

     int n;

     int i, j, k;

     Point_t p;

 #ifndef ONLINE_JUDGE

     freopen("data.in", "r", stdin);

 #endif

     scanf("%d", &t);

     while (t--) {

         scanf("%d %d", &case_n, &n);

         for (i=; i<n; ++i)

             scanf("%d %d", &points[i].x, &points[i].y);

         Graham(n);

         printf("%d %d\n", case_n, top+);

         p = stack[];

         k = ;

         for (i=; i<=top; ++i) {

             if (stack[i].y>p.y || (stack[i].y==p.y && stack[i].x<p.x)) {

                 p = stack[i];

                 k = i;

             }

         }

         for (i=k; i>=; --i)

             printf("%d %d\n", stack[i].x, stack[i].y);

         for (i=top; i>k; --i)

             printf("%d %d\n", stack[i].x, stack[i].y);

     }

     return ;

 }