From adjacency matrix to the list of edges

The simple not oriented graph is given by the adjacency matrix. Print its representation as a list of edges.

Input

The first line contains the number n (1 ≤ n ≤ 100) of vertices in a graph. Each of the next n lines contains n elements - the description of adjacency matrix.

Output

Print the list of edges, ordered by the first vertex in a pair that describes an edge.

Examples