import java.util.*;

class Node {
    char value;
    Node left;
    Node right;

    public Node(char value) {
        this.value = value;
        this.left = null;
        this.right = null;
    }
}

class Tree {
    Node[] data;

    public Tree(int N) {
        this.data = new Node[N];
    }

    public void insertNode_byCharlist(char[] char_list) {
        char root = char_list[0];
        char left = char_list[1];
        char right = char_list[2];

        if(data[root-'A'] == null) {
            data[root-'A'] = new Node(root);
        }

        if('A'<=left && left<='Z') {
            if(data[left-'A'] == null) data[left-'A'] = new Node(left);
            data[root-'A'].left = data[left-'A'];
        }

        if('A'<=right && right<='Z') {
            if(data[right-'A'] == null) data[right-'A'] = new Node(right);
            data[root-'A'].right = data[right-'A'];
        }
    }

    public void preorder() {
        preorder(this.data[0]);
        System.out.println();
    }

    public void inorder() {
        inorder(this.data[0]);
        System.out.println();
    }

    public void postorder() {
        postorder(this.data[0]);
        System.out.println();
    }

    private void preorder(Node node) {
        if (node == null) return;

        System.out.print(node.value);
        preorder(node.left);
        preorder(node.right);
    }

    private void inorder(Node node) {
        if (node == null) return;

        inorder(node.left);
        System.out.print(node.value);
        inorder(node.right);
    }

    private void postorder(Node node) {
        if (node == null) return;
        
        postorder(node.left);
        postorder(node.right);
        System.out.print(node.value);
    }
}

public class _1991 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int N = Integer.parseInt(sc.nextLine());
        Tree tree = new Tree(N);
        for(int i=0; i<N; i++) {
            char[] input = sc.nextLine().replace(" ", "").toCharArray();
            tree.insertNode_byCharlist(input);
        }
        sc.close();

        tree.preorder();
        tree.inorder();
        tree.postorder();
    }
}