#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 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<set<int>> x(k), y(k);
    REP(i,h)REP(j,w){
        if(a[i][j]==0)
            continue;
        int p=mp[a[i][j]]-1;
        x[p].insert(i);
        y[p].insert(j);
    }
    int ans=0;
    REP(i,k-1){
        ans+=min(x[i].size(),y[i].size());
    }
    cout << ans << endl;
    return 0;
}