/* -*- coding: utf-8 -*-
 *
 * 2178.cc:  No.2178 Payable Magic Items - yukicoder
 */

#include<cstdio>
#include<vector>
#include<queue>
#include<algorithm>
 
using namespace std;

/* constant */

const int MAX_N = 200000;
const int MAX_K = 8;
const int MAX_M = 390625; // = 5^8

/* typedef */

typedef vector<int> vi;
typedef queue<int> qi;

/* global variables */

char s[MAX_K + 4];
vi vs[MAX_N];
bool used[MAX_M];

/* subroutines */

int v2id(vi &v) {
  int id = 0;
  for (int i = 0, e = 1; i < v.size(); i++, e *= 5) id += v[i] * e;
  return id;
}

void id2v(int id, int k, vi &v) {
  v.resize(k);
  for (int i = 0; i < k; i++, id /= 5) v[i] = id % 5;
}

/* main */

int main() {
  int n, k;
  scanf("%d%d", &n, &k);

  for (int i = 0; i < n; i++) {
    scanf("%s", s);
    vs[i].resize(k);
    for (int j = 0; j < k; j++) vs[i][j] = s[j] - '0';
  }
  sort(vs, vs + n);
  
  int cnt = 0;
  for (int i = n - 1; i >= 0; i--) {
    int st = v2id(vs[i]);
    if (used[st]) cnt++;
    else {
      used[st] = true;
      qi q;
      q.push(st);

      while (! q.empty()) {
	int u = q.front(); q.pop();
	vi uv;
	id2v(u, k, uv);

	for (int j = 0; j < k; j++)
	  if (uv[j] > 0) {
	    uv[j]--;
	    int v = v2id(uv);
	    if (! used[v]) {
	      used[v] = true;
	      q.push(v);
	    }
	    uv[j]++;
	  }
      }
    }
  }

  printf("%d\n", cnt);
  return 0;
}