#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef pair<ll,ll> P;
typedef vector<ll> VI;
typedef vector<VI> VVI;
#define REP(i,n) for(ll i=0;i<(n);i++)
#define ALL(v) v.begin(),v.end()
constexpr ll MOD=998244353;
constexpr ll INF=2e18;

int f(vector<P> p){
    int n=p.size();
    VI used(n,0);
    int ret=0;
    while(1){
        ret++;
        map<int,int> x, y;
        REP(i,n){
            if(!used[i]){
                x[p[i].first]++;
                y[p[i].second]++;
            }
        }
        int maxx=0, xx, maxy=0, yy;
        for(auto q:x){
            if(maxx<q.second){
                maxx=q.second;
                xx=q.first;
            }
        }
        for(auto q:y){
            if(maxy<q.second){
                maxy=q.second;
                yy=q.first;
            }
        }
        bool bre=1;
        REP(i,n){
            if(!used[i]){
                if(maxx>maxy){
                    if(p[i].first==xx)
                        used[i]=1;
                    else
                        bre=0;
                }
                else{
                    if(p[i].second==yy)
                        used[i]=1;
                    else
                        bre=0;
                }
            }
        }
        if(bre)
            break;
    }
    return ret;
}

int main(){
    int h, w; cin >> h >> w;
    VVI a(h,VI(w));
    REP(i,h)REP(j,w) cin >> a[i][j];
    map<int,int> mp; int k=1;
    REP(i,h)REP(j,w){
        if(a[i][j]==0)
            continue;
        if(mp[a[i][j]]==0){
            mp[a[i][j]]=k;
            k++;
        }
    }
    vector<vector<P>> p(k);
    REP(i,h)REP(j,w){
        if(a[i][j]==0)
            continue;
        int id=mp[a[i][j]]-1;
        p[id].push_back({i,j});
    }
    int ans=0;
    REP(i,k-1){
        ans+=f(p[i]);
    }
    cout << ans << endl;
    return 0;
}