Historical Pathways

You are given an m x n grid representing a historical map where certain cells are blocked (represented by 1) and the rest are open (represented by 0). You start at the top left corner of the grid and need to find all unique paths to the bottom right corner. Each path can only move down or right, and you must return all unique paths in lexicographically sorted order. If no path exists, return "No valid paths". Input Format: - The first line contains two integers m and n (1 ≤ m, n ≤ 10). - The following m lines contain n integers each representing the grid (0 for open cell, 1 for blocked cell). Output Format: - Print each unique path as a string of coordinates (e.g., "(0,0) -> (0,1) -> (1,1)"). If no valid paths exist, print "No valid paths". Example: Input: 2 2 0 0 0 0 Output: (0,0) -> (0,1) -> (1,1)