import sys
input = sys.stdin.readline

N,M=map(int,input().split())
S=[input().strip() for i in range(M)]

A="0"*N
B="1"*N

if A in S and B in S:
    pass
else:
    print("No")
    exit()

for i in range(M):
    for j in range(i+1,M):
        X=S[i]
        Y=S[j]

        Z=[]
        W=[]

        for k in range(N):
            if X[k]=="1" or Y[k]=="1":
                Z.append("1")
            else:
                Z.append("0")

            if X[k]=="0" or Y[k]=="0":
                W.append("0")
            else:
                W.append("1")

        Z="".join(Z)
        W="".join(W)

        if Z in S and W in S:
            pass
        else:
            print("No")
            exit()

print("Yes")