#include<stdio.h>
#include<iostream>
#include<vector>
using namespace std;
typedef struct node{
    int data;
    node *next;
}linklist;
linklist *mergeTwoLists(linklist *head1,linklist *head2){
    linklist *head,*p;
    head=(linklist*)malloc(sizeof(linklist));
    head1=head1->next;
    head2=head2->next;
    p=head;
    while(head1!=NULL&&head2!=NULL){
        if(head1->data<head2->data){
            p->next=head1;
            head1=head1->next;
            p=p->next;
        }
        else{
            p->next=head2;
            head2=head2->next;
            p=p->next;
        }
    }
    if(head1!=NULL){
        p->next=head1;
    }
    if(head2!=NULL){
        p->next=head2;
    }
    return head;
}
void main(){
        /*int n,m;
    scanf("%d%d",&n,&m);
    linklist *head1,*k1,*head2,*k2,*head;
    head1=(linklist*)malloc(sizeof(linklist));
    head1->next=NULL;
    k1=head1;
    for(int i=0;i<n;i++){
        linklist *p;
        p=(linklist*)malloc(sizeof(linklist));
        scanf("%d",&p->data);
        p->next=k1->next;
        k1->next=p;
        k1=p;

    }
    head2=(linklist*)malloc(sizeof(linklist));
    head2->next=NULL;
    k2=head2;
    for(int i=0;i<n;i++){
        linklist *p;
        p=(linklist*)malloc(sizeof(linklist));
        scanf("%d",&p->data);
        p->next=k2->next;
        k2->next=p;
        k2=p;

    }
    head=(linklist*)malloc(sizeof(linklist));
    head=mergeTwoLists(head1,head2);
    while(head->next!=NULL){
        printf("%d",head->next->data);
        head=head->next;
    }*/
    //vector<linklist*> list;
    linklist *list[20];
    int k;
    scanf("%d",&k);
    for(int i=0;i<k;i++){
        list[i]=(linklist*)malloc(sizeof(linklist));
        list[i]->next=NULL;
        linklist *t=list[i];
        for(int i=0;i<3;i++){
            linklist *p;
            p=(linklist*)malloc(sizeof(linklist));
            scanf("%d",&p->data);
            p->next=t->next;
            t->next=p;
            t=p;

        }   
    }
    for(int i=1;i<k;i++){
        list[i]=mergeTwoLists(list[i-1],list[i]);
    }
    linklist *head=list[k-1];
    while(head->next!=NULL){
        printf("%d",head->next->data);
        head=head->next;
    }
}