# [Ceoi2013]board

时间限制：1s 【提交】 空间限制：256MB

### 题目描述

Mirko and Slavko have a new board game. The game board resembles a complete infinite binary tree. More precisely, the board consists of nodes and two-way roads connecting them. The root node is located at the

top of the board and we say it is at

*level zero*. Each node has exactly two children, the*left child*and the*right child*, located in the lower-left and the lower-right directions of the parent node. The level of a

child node is one greater than the level of the parent node. In addition to roads connecting a parent node with its children, there are roads connecting all of the nodes at a particular level – for each level, starting from the leftmost node, there is a road connecting each node to the next node to the right on the same level.

**Figure 1: The second test example below**

Each

*path*through the game board is a sequence of steps, each moving from a node to a different node viaa single road. Each step can be described by a single character as follows:

· character „1