#include<iostream>
#include<queue>
#include<cstdio>
#include<algorithm>
#include<cstring>
#include<iomanip>
#include<map>
#include<cstdlib>
#include<cmath>
const double eps=1e-8;
const double PI=3.1415926;
const int Max=1001;
#define zero(x) (((x)>0?(x):-(x))<eps)
using namespace std;
int sign(double x)
{
    return (x>eps)-(x<-eps);
}
typedef struct Node
{
    double x;
    double y;
}point;
point list[Max],stack[Max];
int n;
int top;
double xmult(point p0,point p1,point p2)
{
	return(p1.x-p0.x)*(p2.y-p0.y)-(p2.x-p0.x)*(p1.y-p0.y);
}
double Distance(point p1,point p2)// 返回两点之间欧氏距离
{
	return( sqrt( (p1.x-p2.x)*(p1.x-p2.x)+(p1.y-p2.y)*(p1.y-p2.y) ) );
}
double slope(point u,point v)
{
    return (v.y-u.y)/(v.x-u.x);
}
bool cmp(point p1,point p2)
{
    double temp;
    temp=xmult(list[0],p1,p2);
    if(temp>0)
        return true;
    if(temp==0&&(Distance(list[0],p1)<Distance(list[0],p2)))
        return true;
    return false;
}
void convex_hull()//凸包模板
{
    int i;
    sort(list+1,list+n,cmp);
    top=1;
    stack[0]=list[0];
    stack[1]=list[1];
    for(i=2;i<n;i++)
    {
        while(top>=1&&xmult(stack[top-1],stack[top],list[i])<=0)
            top--;
        top++;
        stack[top]=list[i];
    }
}
int main()
{
    int m,i,j,t;
    n=0;
    while(cin>>list[n].x>>list[n].y)
    {
        n++;
    }
    convex_hull();
    for(i=0;i<=top;i++)
    {
        cout<<"("<<stack[i].x<<","<<stack[i].y<<")"<<endl;
    }
    return 0;
}