from collections import defaultdict class UnionFind(): def __init__(self, n): self.n = n self.parents = [-1] * n def find(self, x): way=[] while True: if self.parents[x] < 0: break else: way.append(x) x=self.parents[x] for w in way: self.parents[w]=x return x def union(self, x, y): x = self.find(x) y = self.find(y) if x == y: return if self.parents[x] > self.parents[y]: x, y = y, x self.parents[x] += self.parents[y] self.parents[y] = x def size(self, x): return -self.parents[self.find(x)] def same(self, x, y): return self.find(x) == self.find(y) def members(self, x): root = self.find(x) return [i for i in range(self.n) if self.find(i) == root] def roots(self): return [i for i, x in enumerate(self.parents) if x < 0] def group_count(self): return len(self.roots()) def all_group_members(self): group_members = defaultdict(list) for member in range(self.n): group_members[self.find(member)].append(member) return group_members def __str__(self): return '\n'.join(f'{r}: {m}' for r, m in self.all_group_members().items()) N,M=map(int,input().split()) S=set() for _ in range(M): S.add(input()) if '1'*N not in S: print('No') exit(0) Flag=[[True for _ in range(N)] for _ in range(N)] for s in S: for i in range(N): for j in range(N): if s[i]!=s[j]: Flag[i][j]=False uf=UnionFind(N) for i in range(N): for j in range(N): if Flag[i][j]: uf.union(i,j) #print(Flag) #print(uf.group_count()) if 2**uf.group_count()>len(S): print('No') else: print('Yes')