#python -m pdb a.py

I,R=input,range
M,N=map(int,I().split())
D=30
B=(N+D-1)//D
def S(s):return [int(s[k*D:(k+1)*D][::-1],2)for k in R(B)]
a=S('1'*N)
n=[a[:]for i in R(N)]
for j in R(M):
	s=I();b=S(s)
	for i in R(N):
		if s[i]=='1':
			for k in R(B):
				n[i][k]&=b[k]
c=N
P=list(R(N))
H=[0]*N
def r(i):
	m=P[i]
	while i!=m:P[i]=i=P[m];m=P[i]
	return i
for i in R(N):
	for j in R(N):
		if n[i][j//D]>>(j%D)&1:
			u,v=r(i),r(j)
			if H[v]<H[u]:u,v=v,u
			H[v]+=H[u]==H[v];P[u]=v;c-=u!=v
print(c)