import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintStream;
import java.io.StreamTokenizer;
import java.util.InputMismatchException;


public class Main {

	public static Node[] nodes;

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in); 
		Printer pr = new Printer(System.out);

		int n = sc.nextInt();
		nodes = new Node[n];
		
    	for (int i = 0; i < n; i++) {
    		int id = sc.nextInt();
    		nodes[id] = new Node(id, sc.nextInt(), sc.nextInt());
    	}

    	for (int i = 0; i < n; i++) {
    		setParent(i);
    	}
    	int root = seekRoot();

//    	setDepth(root, 0);
//    	for (int i = 0; i < n; i++) {
//        	setHeight(i);
//    	}


//    	for (int i = 0; i < n; i++) {
//    		pr.println(nodes[i].toString());
//    	}

    	int[] order = new int[n];
    	// Preorder
    	if (preorder(root, order, 0) != n) {
    		pr.println("Error");
    	}
    	
    	pr.println("Preorder");
    	pr.print(" ");
    	pr.printArray(order);
    	
    	// Inorder
    	if (inorder(root, order, 0) != n) {
    		pr.println("Error");
    	}
    	
    	pr.println("Inorder");
    	pr.print(" ");
    	pr.printArray(order);
    	
    	// Postorder
    	if (postorder(root, order, 0) != n) {
    		pr.println("Error");
    	}
    	
    	pr.println("Postorder");
    	pr.print(" ");
    	pr.printArray(order);
    	
    	pr.close();
        sc.close();
	}

	private static int preorder(int id, int[] order, int k) {
		order[k] = id;
		k++;
		
		if (nodes[id].l_child != -1) {
			k = preorder(nodes[id].l_child, order, k);
		}
		
		if (nodes[id].r_child != -1) {
			k = preorder(nodes[id].r_child, order, k);
		}

		return k;
		
	}
	
	private static int inorder(int id, int[] order, int k) {
		if (nodes[id].l_child != -1) {
			k = inorder(nodes[id].l_child, order, k);
		}
		
		order[k] = id;
		k++;
		
		if (nodes[id].r_child != -1) {
			k = inorder(nodes[id].r_child, order, k);
		}

		return k;
		
	}
	
	private static int postorder(int id, int[] order, int k) {
		if (nodes[id].l_child != -1) {
			k = postorder(nodes[id].l_child, order, k);
		}
		
		if (nodes[id].r_child != -1) {
			k = postorder(nodes[id].r_child, order, k);
		}

		order[k] = id;
		k++;
		
		return k;
		
	}
	
	private static void setParent(int id) {
		nodes[id].degree = 0;
		if (nodes[id].l_child != -1) {
			nodes[nodes[id].l_child].parent = id;
			nodes[id].degree++;
		}
		if (nodes[id].r_child != -1) {
			nodes[nodes[id].r_child].parent = id;
			nodes[id].degree++;
		}
	}
	
	private static int seekRoot() {
    	for (int i = 0; i < nodes.length; i++) {
    		if (nodes[i].parent == -1){
    			return i;
    		}
    	}
    	
    	return -1;
	}
	
//	private static void setDepth(int id, int depth) {
//		if (nodes[id].parent == -1) {
//			nodes[id].type = NodeType.ROOT;
//		} else {
//			if (nodes[id].degree == 0) {
//				nodes[id].type = NodeType.LEAF;
//				nodes[id].height = 0;
//			} else {
//				nodes[id].type = NodeType.INTERNAL_NODE;
//				nodes[id].height = -1;
//			}
//		}
//		nodes[id].depth = depth;
//
//		if (nodes[id].degree == 2) {
//			nodes[nodes[id].l_child].sibling = nodes[id].r_child;
//			nodes[nodes[id].r_child].sibling = nodes[id].l_child;
//		}
//		
//		if (nodes[id].l_child != -1) {
//			setDepth(nodes[id].l_child, depth + 1);
//		}
//		if (nodes[id].r_child != -1) {
//			setDepth(nodes[id].r_child, depth + 1);
//		}
//
//		return;
//	}
		
//	private static void setHeight(int id) {
//		if (nodes[id].height != 0) {
//			return;
//		} else {
//			for (int j = nodes[id].parent, h = 0; j != -1; j = nodes[j].parent, h++) {
//				if (nodes[j].height < h + 1) {
//					nodes[j].height = h + 1;
//				}
//			}
//		}
//	}

	private static enum NodeType {
		ROOT, INTERNAL_NODE, LEAF;
	}
	
	private static class Node {
		public int id;
		public int parent;
		public int l_child;
		public int r_child;
		public int sibling;
		public int depth;
		public int height;
		public int degree;
		public NodeType type;
	
		public Node(int id, int l_child, int r_child) {
			this.id = id;
			this.l_child = l_child;
			this.r_child = r_child;
			this.sibling = -1;
			this.parent = -1;
		}
		
		@Override
		public String toString() {
			StringBuffer str = new StringBuffer();

			str.append("node ");
			str.append(id);
			str.append(": parent = ");
			str.append(parent);
			str.append(", sibling = ");
			str.append(sibling);
			str.append(", degree = ");
			str.append(degree);
			str.append(", depth = ");
			str.append(depth);
			str.append(", height = ");
			str.append(height);
			str.append(", ");
			String type;
			switch (nodes[id].type) {
			case INTERNAL_NODE:
				type = "internal node";
				break;
			case LEAF:
				type = "leaf";
				break;
			case ROOT:
				type = "root";
				break;
			default:
				type = null;
			}
			str.append(type);
			
			return str.toString();
		}
	}


	private static class Scanner {
		InputStreamReader isr;
		BufferedReader br;
		StreamTokenizer st;
		
		Scanner (InputStream in) {
			isr = new InputStreamReader(in);
			br = new BufferedReader(isr);
			st = new StreamTokenizer(br);
		}
		
		String next() throws RuntimeException  {
			try {
				if (st.nextToken() != StreamTokenizer.TT_WORD) {
				}
			} catch (IOException e) {
				throw new IllegalStateException();
			}
			
			return st.sval;
		}
		
		int nextInt() throws RuntimeException {
			try {
				if (st.nextToken() != StreamTokenizer.TT_NUMBER) {
					throw new InputMismatchException();
				}
			} catch (IOException e) {
				throw new IllegalStateException();
			}
			
			return (int)st.nval;
		}

		void close() {
		}
	}
	
	private static class Printer {
		PrintStream out;
		StringBuffer strbuf;
		int bufSize;
		final String CR;

		Printer(PrintStream out) {
			this.out = out;
			strbuf = new StringBuffer();
			bufSize = 64 * 1024;
			CR = System.getProperty("line.separator");
		}

		void println(String str) {
			strbuf.append(str);
			strbuf.append(CR);
			checkStringBuffer();
		}

		void print(String str) {
			strbuf.append(str);
			checkStringBuffer();
		}

		void println(int n) {
			strbuf.append(n);
			strbuf.append(CR);
			checkStringBuffer();
		}

		void print(int n) {
			strbuf.append(n);
			checkStringBuffer();
		}

		void print(char c) {
			strbuf.append(c);
			checkStringBuffer();
		}

		void printArray(int[] array) {
			for (int i = 0; i < array.length; i++) {
				checkStringBuffer();
				strbuf.append(array[i]);
				strbuf.append(" ");
			}
			strbuf.delete(strbuf.length() - 1, strbuf.length());
			strbuf.append(CR);
		}

		void close() {
			flashStringBuffer();
		}
		
		private void flashStringBuffer() {
			if (strbuf.length() > 0) {
				out.print(strbuf);
				strbuf.setLength(0);
			}
		}
		
		private void checkStringBuffer() {
			if (strbuf.length() > bufSize) {
				out.print(strbuf);
				strbuf.setLength(0);
			}
		}
	}
}

Measured memory_bytes: 17032