#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <string>
#include <algorithm>
#include <iostream>
#include <functional>
using namespace std;

struct Point {
    int x, y;
} points[60];

bool cmpCoord(Point a, Point b) {
    return a.y == b.y ? a.x < b.x : a.y > b.y;
}

int len2(Point a, Point b) {
    return (b.x - a.x) * (b.x - a.x) + (b.y - a.y) * (b.y - a.y);
}

int area(Point a, Point b, Point c) {
    return (b.x - a.x) * (c.y - a.y) - (b.y - a.y) * (c.x - a.x);
}

bool cmpAngle(Point a, Point b) {
    return area(points[0], a, b) == 0 ? len2(points[0], a) < len2(points[0], b) : area(points[0], a, b) < 0;
}

int p, n;
vector<Point> hull;

int main() {
    //freopen("input.txt", "r", stdin);
    //freopen("output.txt", "w", stdout);

    scanf("%d", &p);
    for (int tst = 1; tst <= p; tst++) {
        scanf("%*d%d", &n);
        for (int i = 0; i < n; i++)
            scanf("%d%d", &points[i].x, &points[i].y);
        sort(points, points + n, cmpCoord);
        sort(points + 1, points + n, cmpAngle);
        hull.clear();
        hull.push_back(points[0]);
        hull.push_back(points[1]);
        for (int i = 2; i < n; i++) {
            while (hull.size() > 1 && area(hull[hull.size() - 2], hull[hull.size() - 1], points[i]) >= 0)
                hull.pop_back();
            hull.push_back(points[i]);
        }
        printf("%d %d\n", tst, hull.size());
        for (int i = 0; i < hull.size(); i++)
            printf("%d %d\n", hull[i].x, hull[i].y);
    }

    return 0;
}