Competitions

# Depth First Search

# Connected components

The undirected unweighted graph is given. Find the number of its connected components.

#### Input

The first line contains the number of vertices **n** (**n** ≤ **100**) in a graph. In each of the next **n** rows **n** numbers are given - the adjacency matrix of the graph: in the **i**-th row of the **j**-th place there is a **1** if the vertices **i** and **j** are connected by an edge, and **0** otherwise. The main diagonal of the matrix contains zeroes. The matrix is symmetric with respect to the main diagonal.

#### Output

Print the number of connected components in a graph.

Input example #1

6 0 1 1 0 0 0 1 0 1 0 0 0 1 1 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 0 0

Output example #1

3