import numpy as np
import sys
input = sys.stdin.readline

def solve():
	n = int(input())
	m = int(input())
	mat = np.array([np.array(list(input().rstrip())).astype(bool) for _ in [0] * m])
	for i in range(n):
		a = np.prod(np.array([v for v in mat if(v[i])]), axis = 0).astype(bool)
		b = np.sum(np.array([v for v in mat if not(v[i]) ]), axis = 0).astype(bool)
		c = a & ~b
		c[i] = False
		if c.any():
			print("No")
			exit(0)
	print("Yes")

solve()