import java.util.*;
/*
 * Given a valid binary tree representation as follows:
 * a tree might be represented as ( a b c ) where a is the root, b is the left
 * child and b is the right child. Any child/subtree can also be represented as
 * ( a ( b ) ( c ) ), ( a ( b ) c ), ( a b ( c ) ), etc..
 * print the tree in in-order fashion
 */
public class InOrderBT {
	public static void main(String[] args){
		String input = "( v ( a ( b ) ( ( c ) ( d ) ( x ( ) ) ) ) h )";
		Scanner s = new Scanner( input);
		Stack<TNode> stack = new Stack<TNode>();
		List<TNode> lst = new ArrayList<TNode>();
		while(s.hasNext()){
			String n = s.next();						
			if(n.equals(")")){				
				lst.clear();
				while(!stack.peek().isOpenBracket()){
					lst.add(0,stack.pop());
				}
				//pop the "("
				stack.pop();
				if(lst.size() == 1){
					TNode root = lst.get(0);
					stack.push(root);
				}else if(lst.size() == 2){
					TNode root = lst.get(0);
					TNode left = lst.get(1);
					root.setLeft(left);
					stack.push(root);
				}else if(lst.size()==3){
					TNode root = lst.get(0);
					TNode left = lst.get(1);
					TNode right = lst.get(2);
					root.setLeft(left);
					root.setRight(right);
					stack.push(root);	
				}				
			}else stack.push(new TNode(n));
		}		
		TNode.inOrderTraverse(stack.pop());
	}
		
}

class TNode{
	TNode left;
	TNode right;
	String v;
	
	public TNode(String v, TNode left, TNode right){
		this.v = v;
		this.left = left;
		this.right = right;
	}
	public TNode(String v){
		this.v = v;
	}
	public void setLeft(TNode n){ this.left = n;}
	public void setRight(TNode n){ this.right = n;} 
	public boolean isOpenBracket(){
		return v.equals("(");
	}
	public String toString(){
		if(this.v == null) return "";
		return "[ " + this.v + 
			" left : " + ( left == null ? "null" : this.left.v ) +
			" right:" + ( right == null ? "null" : this.right.v) + "]";
		
	}
	public static void inOrderTraverse(TNode node){
		if(node == null) return;
		inOrderTraverse(node.left);
		System.out.print( node.v + " " );
		inOrderTraverse(node.right);
	}
	
}