import sys
from collections import deque
input = sys.stdin.readline

def toNum(s):
	ret = 0
	for c in s:
		k = 3 - (ord(c) - ord('A'))
		ret <<= 2
		ret += k
	return ret

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

init = (1 << (K << 1)) - 1
que = deque([(init, 0)])
sell = [0] * (1 << (K << 1))
visited = [0] * (1 << (K << 1))
visited[init] = 1
while(que):
	v, b = que.pop()
	sell[v] = b
	b |= (v in st)
	for i in range(K):
		k = i << 1
		if(((v >> k) & 3) == 0):
			continue
		nv = v - (1 << k)
		if(visited[nv] == 1):
			continue
		visited[nv] = 1
		if(b == 1):
			que.append((nv, b))
			continue
		que.appendleft((nv, b))

ans = sum(sell[k] for k in st)
print(ans)