#include<bits/stdc++.h>

using namespace std;


#define mp make_pair
#define int long long
using vi = vector<int>;
using pii = pair<int, int>;

const int inf = 1e9;


int n, m, res = 0, cnt;
vector<vi> a;

vi operator^(const vi &a, const vi &b) {
    vi c(n);
    for (int i = 0; i < n; i++)
        c[i] = a[b[i]];
    return c;
}

void init() {
    int x = 1, y = 1;
    for (int i = 1; x <= inf and i <= n; i++)
        x = x * i;
    for (int i = 1; y <= inf and i <= m; i++)
        y = y * 2;
    cnt = min(x, y);
    return;
}

void dfs(int i, set<vi> st) {
    res = max(res, (int) st.size());
    if (i == m) return;
    if (st.size() == cnt) {
        cout << cnt << "\n";
        exit(0);
    }

    dfs(i + 1, st);

    set<vi> cur;
    for (const auto &it: st)
        cur.insert(it ^ a[i]);
    if(!cur.empty()) st.insert(cur.begin(), cur.end());
    st.insert(a[i]);
    dfs(i + 1, st);
    return;
}

int32_t main() {
    ios::sync_with_stdio(false), cin.tie(nullptr);
    cin >> n >> m;
    init();
    a = vector(m, vi(n));
    for (int i = 0; i < m; i++)
        for (int j = 0; j < n; j++)
            cin >> a[i][j], a[i][j]--;

    dfs(0, set<vi>());
    cout << res << "\n";

    return 0;
}