Problems
Count the number of edges
Count the number of edges
The directed graph is given with an adjacency matrix. Find the number of edges in a graph.
Input data
The first line contains the number of vertices in the graph n\:(1 \le n \le 100). Then given n lines with n numbers 0 or 1 — the adjacency matrix of the graph.
Output data
Print the number of edges in a graph.
Examples
Input example #1
3 0 1 1 1 0 1 0 1 1
Output example #1
6