A tournament is a directed graph without self-loops in which every pair of vertexes is connected by exactly one directed edge. That is, for any two vertexes *u* and *v* (*u* ≠ *v*) exists either an edge going from *u* to *v*, or an edge from *v* to *u*.

You are given a tournament consisting of *n* vertexes. Your task is to find there a cycle of length three.

The first line contains an integer *n* (1 ≤ *n* ≤ 5000). Next *n* lines contain the adjacency matrix *A* of the graph (without spaces). *A*_{i, j} = 1 if the graph has an edge going from vertex *i* to vertex *j*, otherwise *A*_{i, j} = 0. *A*_{i, j} stands for the *j*-th character in the *i*-th line.

It is guaranteed that the given graph is a tournament, that is, *A*_{i, i} = 0, *A*_{i, j} ≠ *A*_{j, i} (1 ≤ *i*, *j* ≤ *n*, *i* ≠ *j*).

提交代码