Language: C++

#include <bits/stdc++.h>
#include <sys/time.h>
using namespace std;

#define rep(i,n) for(long long i = 0; i < (long long)(n); i++)
#define repi(i,a,b) for(long long i = (long long)(a); i < (long long)(b); i++)
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define fi first
#define se second
#define mt make_tuple
#define mp make_pair
#define ZERO(a) memset(a,0,sizeof(a))
template<class T1, class T2> bool chmin(T1 &a, T2 b) { return b < a && (a = b, true); }
template<class T1, class T2> bool chmax(T1 &a, T2 b) { return a < b && (a = b, true); }
#define exists find_if
#define forall all_of

using ll = long long; using vll = vector<ll>; using vvll = vector<vll>; using P = pair<ll, ll>;
using ld = long double;  using vld = vector<ld>; 
using vi = vector<int>; using vvi = vector<vi>; vll conv(vi& v) { vll r(v.size()); rep(i, v.size()) r[i] = v[i]; return r; }
using Pos = complex<double>;

template <typename T, typename U> ostream &operator<<(ostream &o, const pair<T, U> &v) {  o << "(" << v.first << ", " << v.second << ")"; return o; }
template<size_t...> struct seq{}; template<size_t N, size_t... Is> struct gen_seq : gen_seq<N-1, N-1, Is...>{}; template<size_t... Is> struct gen_seq<0, Is...> : seq<Is...>{};
template<class Ch, class Tr, class Tuple, size_t... Is>
void print_tuple(basic_ostream<Ch,Tr>& os, Tuple const& t, seq<Is...>){ using s = int[]; (void)s{0, (void(os << (Is == 0? "" : ", ") << get<Is>(t)), 0)...}; }
template<class Ch, class Tr, class... Args> 
auto operator<<(basic_ostream<Ch, Tr>& os, tuple<Args...> const& t) -> basic_ostream<Ch, Tr>& { os << "("; print_tuple(os, t, gen_seq<sizeof...(Args)>()); return os << ")"; }
ostream &operator<<(ostream &o, const vvll &v) { rep(i, v.size()) { rep(j, v[i].size()) o << v[i][j] << " "; o << endl; } return o; }
template <typename T> ostream &operator<<(ostream &o, const vector<T> &v) { o << '['; rep(i, v.size()) o << v[i] << (i != v.size()-1 ? ", " : ""); o << "]";  return o; }
template <typename T>  ostream &operator<<(ostream &o, const set<T> &m) { o << '['; for (auto it = m.begin(); it != m.end(); it++) o << *it << (next(it) != m.end() ? ", " : ""); o << "]";  return o; }
template <typename T, typename U>  ostream &operator<<(ostream &o, const map<T, U> &m) { o << '['; for (auto it = m.begin(); it != m.end(); it++) o << *it << (next(it) != m.end() ? ", " : ""); o << "]";  return o; }
template <typename T, typename U, typename V>  ostream &operator<<(ostream &o, const unordered_map<T, U, V> &m) { o << '['; for (auto it = m.begin(); it != m.end(); it++) o << *it; o << "]";  return o; }
vector<int> range(const int x, const int y) { vector<int> v(y - x + 1); iota(v.begin(), v.end(), x); return v; }
template <typename T> istream& operator>>(istream& i, vector<T>& o) { rep(j, o.size()) i >> o[j]; return i;}
string bits_to_string(ll input, ll n=64) { string s; rep(i, n) s += '0' + !!(input & (1ll << i)); reverse(all(s)); return s; }

template <typename T> unordered_map<T, ll> counter(vector<T> vec){unordered_map<T, ll> ret; for (auto&& x : vec) ret[x]++; return ret;};
string substr(string s, P x) {return s.substr(x.fi, x.se - x.fi); }
struct ci : public iterator<forward_iterator_tag, ll> { ll n; ci(const ll n) : n(n) { } bool operator==(const ci& x) { return n == x.n; } bool operator!=(const ci& x) { return !(*this == x); } ci &operator++() { n++; return *this; } ll operator*() const { return n; } };

size_t random_seed; namespace std { using argument_type = P; template<> struct hash<argument_type> { size_t operator()(argument_type const& x) const { size_t seed = random_seed; seed ^= hash<ll>{}(x.fi); seed ^= (hash<ll>{}(x.se) << 1); return seed; } }; }; // hash for various class
namespace myhash{ const int Bsizes[]={3,9,13,17,21,25,29,33,37,41,45,49,53,57,61,65,69,73,77,81}; const int xor_nums[]={0x100007d1,0x5ff049c9,0x14560859,0x07087fef,0x3e277d49,0x4dba1f17,0x709c5988,0x05904258,0x1aa71872,0x238819b3,0x7b002bb7,0x1cf91302,0x0012290a,0x1083576b,0x76473e49,0x3d86295b,0x20536814,0x08634f4d,0x115405e8,0x0e6359f2}; const int hash_key=xor_nums[rand()%20]; const int mod_key=xor_nums[rand()%20]; template <typename T> struct myhash{ std::size_t operator()(const T& val) const { return (hash<T>{}(val)%mod_key)^hash_key; } }; };
template <typename T> class uset:public std::unordered_set<T,myhash::myhash<T>> { using SET=std::unordered_set<T,myhash::myhash<T>>; public: uset():SET(){SET::rehash(myhash::Bsizes[rand()%20]);} };
template <typename T,typename U> class umap:public std::unordered_map<T,U,myhash::myhash<T>> { public: using MAP=std::unordered_map<T,U,myhash::myhash<T>>; umap():MAP(){MAP::rehash(myhash::Bsizes[rand()%20]);} };    

struct timeval start; double sec() { struct timeval tv; gettimeofday(&tv, NULL); return (tv.tv_sec - start.tv_sec) + (tv.tv_usec - start.tv_usec) * 1e-6; }
struct init_{init_(){ gettimeofday(&start, NULL); ios::sync_with_stdio(false); cin.tie(0); srand((unsigned int)time(NULL)); random_seed = RAND_MAX / 2 + rand() / 2; }} init__;

static const double EPS = 1e-14;
static const long long INF = 1e18;
static const long long mo = 1e9+7;
#define ldout fixed << setprecision(40) 

const int nmax = 300;

int ret = INF;
int n, m; 
vvint a;
void print(void) {
    cout << "#############" << endl;
    rep(i, a.size()) {
        rep(j, a[i].size()) {
            cout << a[i][j] + 1 << " ";
        }
        cout << endl;
    }
}
void dfs(void) {
    if (!a[0].size()) return;
//    print();
//    cout << a[0].size() << endl;

    int counter[nmax] = {};
    rep(i, n) 
        counter[a[i][0]]++;

    int M = -1;
    rep(i, nmax) 
        chmax(M, counter[i]);
    chmin(ret, M);
    

    vvint a_org = a;
    rep(i, nmax) if (counter[i] == M) {
        vvint a_next(n);
        rep(j, n) rep(h, a_org[j].size()) if (a_org[j][h] != i) {
            a_next[j].pb(a_org[j][h]);
        }
        a = a_next;
        dfs();
        a = a_org;
        break;
    }

}
int main(void) {
    cin >> n >> m;
    rep(i, n) {
        vector<int> tmp;
        rep(i, m) {
            int x; cin >> x; x--;
            tmp.pb(x);
        }
        a.pb(tmp);
    }

    dfs();
    cout << ret << endl;


    return 0;
}


Compiler output:
a.cc:41:20: warning: 'template<class _Category, class _Tp, class _Distance, class _Pointer, class _Reference> struct std::iterator' is deprecated [-Wdeprecated-declarations]
   41 | struct ci : public iterator<forward_iterator_tag, ll> { ll n; ci(const ll n) : n(n) { } bool operator==(const ci& x) { return n == x.n; } bool operator!=(const ci& x) { return !(*this == x); } ci &operator++() { n++; return *this; } ll operator*() const { return n; } };
      |                    ^~~~~~~~
In file included from /usr/include/c++/14/bits/stl_algobase.h:65,
                 from /usr/include/c++/14/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51,
                 from a.cc:1:
/usr/include/c++/14/bits/stl_iterator_base_types.h:127:34: note: declared here
  127 |     struct _GLIBCXX17_DEPRECATED iterator
      |                                  ^~~~~~~~
a.cc:58:11: warning: overflow in conversion from 'long long int' to 'int' changes value from '1000000000000000000' to '-1486618624' [-Woverflow]
   58 | int ret = INF;
      |           ^~~
a.cc:60:1: error: 'vvint' does not name a type; did you mean 'vvi'?
   60 | vvint a;
      | ^~~~~
      | vvi
a.cc: In function 'void print()':
a.cc:63:12: error: 'a' was not declared in this scope
   63 |     rep(i, a.size()) {
      |            ^
a.cc:5:55: note: in definition of macro 'rep'
    5 | #define rep(i,n) for(long long i = 0; i < (long long)(n); i++)
      |                                                       ^
a.cc: In function 'void dfs()':
a.cc:71:10: error: 'a' was not declared in this scope
   71 |     if (!a[0].size()) return;
      |          ^
a.cc:77:17: error: 'a' was not declared in this scope
   77 |         counter[a[i][0]]++;
      |                 ^
a.cc:85:5: error: 'vvint' was not declared in this scope; did you mean 'vvi'?
   85 |     vvint a_org = a;
      |     ^~~~~
      |     vvi
a.cc:87:14: error: expected ';' before 'a_next'
   87 |         vvint a_next(n);
      |              ^~~~~~~
      |              ;
a.cc:88:26: error: 'a_org' was not declared in this scope
   88 |         rep(j, n) rep(h, a_org[j].size()) if (a_org[j][h] != i) {
      |                          ^~~~~
a.cc:5:55: note: in definition of macro 'rep'
    5 | #define rep(i,n) for(long long i = 0; i < (long long)(n); i++)
      |                                                       ^
a.cc:89:13: error: 'a_next' was not declared in this scope
   89 |             a_next[j].pb(a_org[j][h]);
      |             ^~~~~~
a.cc:91:9: error: 'a' was not declared in this scope
   91 |         a = a_next;
      |         ^
a.cc:91:13: error: 'a_next' was not declared in this scope
   91 |         a = a_next;
      |             ^~~~~~
a.cc:93:13: error: 'a_org' was not declared in this scope
   93 |         a = a_org;
      |             ^~~~~
a.cc: In function 'int main()':
a.cc:106:9: error: 'a' was not declared in this scope
  106 |         a.pb(tmp);
      |         ^