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.