/* in the name of Anton */

/*
  Compete against Yourself.
  Author - Aryan Choudhary (@aryanc403)
*/

#pragma GCC optimize ("Ofast")
#pragma GCC target ("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx")
#pragma GCC optimize ("-ffloat-store")

#include<iostream>
#include<bits/stdc++.h>
using namespace std;
#define fo(i,n)   for(i=0;i<(n);++i)
#define repA(i,j,n)   for(i=(j);i<=(n);++i)
#define repD(i,j,n)   for(i=(j);i>=(n);--i)
#define all(x) begin(x), end(x)
#define sz(x) ((lli)(x).size())
#define pb push_back
#define mp make_pair
#define X first
#define Y second
#define endl "\n"

typedef long long int lli;
typedef long double mytype;
typedef pair<lli,lli> ii;
typedef vector<ii> vii;
typedef vector<lli> vi;


const auto start_time = std::chrono::high_resolution_clock::now();
void aryanc403()
{
#ifdef ARYANC403
auto end_time = std::chrono::high_resolution_clock::now();
std::chrono::duration<double> diff = end_time-start_time;
    cerr<<"Time Taken : "<<diff.count()<<"\n";
#endif
}

#ifdef ARYANC403
#include "/home/aryan/codes/PastCodes/header.h"
#else
    #define dbg(args...)
#endif

const lli INF = 0xFFFFFFFFFFFFFFFL;

lli seed;
mt19937 rng(seed=chrono::steady_clock::now().time_since_epoch().count());
inline lli rnd(lli l=0,lli r=INF)
{return uniform_int_distribution<lli>(l,r)(rng);}

class CMP
{public:
bool operator()(ii a , ii b) //For min priority_queue .
{    return ! ( a.X < b.X || ( a.X==b.X && a.Y <= b.Y ));   }};

void add( map<lli,lli> &m, lli x,lli cnt=1)
{
    auto jt=m.find(x);
    if(jt==m.end())         m.insert({x,cnt});
    else                    jt->Y+=cnt;
}

void del( map<lli,lli> &m, lli x,lli cnt=1)
{
    auto jt=m.find(x);
    if(jt->Y<=cnt)            m.erase(jt);
    else                      jt->Y-=cnt;
}

bool cmp(const ii &a,const ii &b)
{
    return a.X<b.X||(a.X==b.X&&a.Y<b.Y);
}

const lli mod = 1000000007L;
// const lli maxN = 1000000007L;

    lli T,n,i,j,k,in,cnt,u,v,x,y;
    lli m;
    string s;
    vector<vi> a;
    //priority_queue < ii , vector < ii > , CMP > pq;// min priority_queue .

bool chk(lli mm,vector<vi> a)
{
    map<lli,vi> m;
    dbg(mm,a)
    fo(i,n)
        m[a[i].back()].pb(i);
    set<lli> rmv;
    while(true)
    {
        vi rm,rmd;
        for(auto &v:m)
        {
            if(sz(v.Y)<=mm)
                continue;
            for(auto y:v.Y)
                rm.pb(y);
            rmv.insert(v.X);
            rmd.pb(v.X);
        }

        dbg(mm,rmd,m)
        for(auto x:rmd)
            m.erase(m.find(x));

        if(rm.empty())
            return true;
        for(auto y:rm)
        {
            while(true)
            {
                if(a[y].empty())
                    return false;
                auto jj=a[y].back();
                if(rmv.find(jj)!=rmv.end())
                {
                    a[y].pop_back();
                    continue;
                }
                break;
            }
            auto jj=a[y].back();
            m[jj].pb(y);
        }
    }
    return true;
}

int main(void) {
    ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
    // freopen("txt.in", "r", stdin);
    // freopen("txt.out", "w", stdout);
// cout<<std::fixed<<std::setprecision(35);
// cin>>T;while(T--)
{

    cin>>n>>m;
    a.resize(n,vi(m,0));
    fo(i,n) fo(j,m)
        cin>>a[i][m-1-j];
    // for(auto v:a)
    //     dbg(v)
    lli l=-1,r=n+2;
    while(r-l>1)
    {
        lli mm=(l+r)/2;
        if(chk(mm,a))
            r=mm;
        else
            l=mm;
    }
    cout<<r<<endl;
}   aryanc403();
    return 0;
}


Measured memory_bytes: 5112