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

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 if(v[i]) else np.zeros(n) for v in mat]), axis = 0).astype(bool)
	b = np.sum(np.array([v if(~v[i]) else np.zeros(n) for v in mat]), axis = 0).astype(bool)
	c = a & ~b
	c[i] &= False
	if c.any():
		print("No")
		exit(0)
print("Yes")