Connected components

Input

The first line contains the number of vertices $n$ (n \leq 100). Then follow $n$ lines with $n$ numbers each — the adjacency matrix of the graph. In the $i$-th row, at the $j$-th position, there is $1$ if vertices $i$ and $j$ are connected by an edge, and $0$ otherwise. The main diagonal of the matrix contains zeros. The matrix is symmetric with respect to the main diagonal.

Output

Print one integer — the number of connected components of the given graph.

Examples