#include<bits/stdc++.h>
namespace {
#pragma GCC diagnostic ignored "-Wunused-function"
#include<atcoder/all>
#pragma GCC diagnostic warning "-Wunused-function"
using namespace std;
using namespace atcoder;
#define rep(i,n) for(int i = 0; i < (int)(n); i++)
#define rrep(i,n) for(int i = (int)(n) - 1; i >= 0; i--)
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
template<class T> bool chmax(T& a, const T& b) { if (a < b) { a = b; return true; } else return false; }
template<class T> bool chmin(T& a, const T& b) { if (b < a) { a = b; return true; } else return false; }
using ll = long long;
using P = pair<int,int>;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<ll>;
using VVL = vector<VL>;

} int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  using BS = bitset<500>;
  int h, w;
  cin >> h >> w;
  vector<BS> a(h);
  rep(i, h) cin >> a[i];
  sort(all(a), [](const BS& x, const BS& y) {
    BS z = x ^ y;
    auto b = z._Find_first();
    return b < x.size() && y[b];
  });
  VI dp(h, 1);
  rrep(i, h) {
    auto t = ~a[i];
    rrep(j, i) if ((t & a[j]).none()) chmax(dp[j], dp[i] + 1);
  }
  cout << h - *max_element(all(dp)) << '\n';
}