import sys
input = sys.stdin.readline

N, K = map(int, input().split())
st = set([input()[:-1] for _ in [0] * N])

visited = set([])
for sv in st:
    if(sv in visited):
        continue
    stk = [sv]
    while(stk):
        v = stk.pop()
        for i in range(K):
            if(v[i] == '0'):
                continue
            nv = ''.join([v[:i], chr(ord(v[i]) - 1), v[i+1:]])
            if(nv in visited):
                continue
            visited.add(nv)
            stk.append(nv)

ans = len(visited & st)
print(ans)