#include <stdio.h>
#include <stdlib.h>

struct Node {
    int n;
    struct Node* nd;
};

int main() {
    struct Node a;
    a.n = 0;
    
    struct Node o;
    o.n = 1;
    a.nd = &o;

    struct Node b;
    b.n = 2;
    o.nd = &b;

    struct Node c;
    c.n = 3;
    b.nd = &c;

    printf("%d %d %d %d", a.n, a.nd -> n, a.nd -> nd -> n, a.nd -> nd -> nd -> n);
    
    return 0;
}