The directed graph is given with an adjacency matrix. Find the number of edges in a graph. \InputFile 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. \OutputFile Print the number of edges in a graph. \includegraphics{https://static.e-olymp.com/content/f6/f6252c9ff7784dea1613accaf4a7f16ea7bbd4cb.gif}