import sys from collections import deque def main(): sys.setrecursionlimit(1 << 25) V, D = map(int, sys.stdin.readline().split()) edges = [] for _ in range(V): line = sys.stdin.readline().strip() adj = [i for i, c in enumerate(line) if c == '1'] edges.append(adj) visited = [False] * V q = deque() visited[0] = True q.append(0) while q: u = q.popleft() for v in edges[u]: if not visited[v]: visited[v] = True q.append(v) if not all(visited): print("No") return color = [-1] * V is_bipartite = True for start in range(V): if color[start] == -1: q = deque() q.append(start) color[start] = 0 while q: u = q.popleft() for v in edges[u]: if color[v] == -1: color[v] = color[u] ^ 1 q.append(v) elif color[v] == color[u]: is_bipartite = False break if not is_bipartite: break if not is_bipartite: break if is_bipartite: print("No") else: print("Yes") if __name__ == "__main__": main()