Number of hanging vertices 1

Execution time limit is 3 seconds

Runtime memory usage limit is 128 megabytes

Given a simple undirected unweighted graph. Count the number of hanging vertices in it. The vertex is hanging, if its degree is $1$ .

Input

The first line contains number $n (1 \leq n \leq 1000)$ . The next $n$ lines contain the adjacency matrix.

Print the number of hanging vertices in a graph.

Input #1

Answer #1

Input #2

Answer #2

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