From adjacency matrix to edge list#4762
A simple undirected graph is defined by an adjacency matrix.
Output its representation as a list of edges.
The first line of the input file contains the number (1 \leq N \leq 100). Then there are lines with elements in each - a description of the adjacency matrix.
In the output file, output a list of edges, ordered first by the first vertex in the pair of vertices that describes the edge, and then by the second.
Example 1