import sys,random,bisect
from collections import deque,defaultdict
from heapq import heapify,heappop,heappush
from itertools import permutations
from math import gcd,log

input = lambda :sys.stdin.readline().rstrip()
mi = lambda :map(int,input().split())
li = lambda :list(mi())

class UnionFindVerSize():
    def __init__(self, N):
        self._parent = [n for n in range(0, N)]
        self._size = [1] * N
        self.group = N

    def find_root(self, x):
        if self._parent[x] == x: return x
        self._parent[x] = self.find_root(self._parent[x])
        return self._parent[x]

    def unite(self, x, y):
        gx = self.find_root(x)
        gy = self.find_root(y)
        if gx == gy: return

        self.group -= 1

        if self._size[gx] < self._size[gy]:
            self._parent[gx] = gy
            self._size[gy] += self._size[gx]
        else:
            self._parent[gy] = gx
            self._size[gx] += self._size[gy]

    def get_size(self, x):
        return self._size[self.find_root(x)]

    def is_same_group(self, x, y):
        return self.find_root(x) == self.find_root(y)


ppp = ord("a")
num = ord("0")

W,H = mi()
uf = UnionFindVerSize(W)
det = [-1] * W
k = W
contra = 0
for _ in range(H):
    S = input()
    tmp = [[] for i in range(26)]
    for i,s in enumerate(S):
        if ppp <= ord(s) < ppp+26:
            tmp[ord(s)-ppp].append(i)
    
    for i in range(26):
        for a,b in zip(tmp[i],tmp[i][1:]):
            if not uf.is_same_group(a,b):
                pa,pb = uf.find_root(a),uf.find_root(b)
                if det[pa]!=-1 and det[pb]!=-1 and det[pa]!=det[pb]:
                    contra = 1
                else:
                    if det[pa] == -1:
                        k -= 1
                    if det[pb] == -1:
                        k -= 1
                    uf.unite(pa,pb)
                    pc = uf.find_root(pa)
                    if det[pa] == -1:
                        det[pc] = det[pb]
                    else:
                        det[pc] = det[pa]
                    if det[pc] == -1:
                        k += 1
    
    for i,s in enumerate(S):
        if num <= ord(s) < num+10:
            s = int(s)
            pi = uf.find_root(i)
            if det[pi] == -1:
                k -= 1
                det[pi] = s
            elif det[pi]!=s:
                contra = 1
    
    
    if contra:
        print(0)
    else:
        print(pow(10,k,998244353))