#include<stdio.h>

struct node{
    int mn;
    struct node *ad;
};

struct node *n1;
int ct=0,s;

void rec(struct node *n1)
{
    ct++;
    scanf("%d",&n1->mn);
    if(ct<=3){
        n1->ad=(struct node *)malloc(s);
        rec(n1->ad);
    }
}


int main()
{
    s=sizeof(struct node);
    n1=(struct node *)malloc(sizeof(struct node));
    rec(n1);
    /*n1=(struct node *)malloc(sizeof(struct node));
    scanf("%d",&n1->mn);
    n1->ad=(struct node *)malloc(sizeof(struct node));
    scanf("%d",&n1->ad->mn);
    n1->ad->ad=(struct node *)malloc(sizeof(struct node));
    scanf("%d",&n1->ad->ad->mn);
    n1->ad->ad->ad=(struct node *)malloc(sizeof(struct node));
    scanf("%d",&n1->ad->ad->ad->mn);*/
    printf("%d %d %d %d\n",n1->mn,n1->ad->mn,n1->ad->ad->mn,n1->ad->ad->ad->mn);
    return 0;
}