#include "bits/stdc++.h" //#include "atcoder/all" using namespace std; //using namespace atcoder; //using mint = modint1000000007; //const int mod = 1000000007; //using mint = modint998244353; //const int mod = 998244353; //const int INF = 1e9; //const long long LINF = 1e18; #define rep(i, n) for (int i = 0; i < (n); ++i) #define rep2(i,l,r)for(int i=(l);i<(r);++i) #define rrep(i, n) for (int i = (n-1); i >= 0; --i) #define rrep2(i,l,r)for(int i=(r-1);i>=(l);--i) #define all(x) (x).begin(),(x).end() #define allR(x) (x).rbegin(),(x).rend() #define endl "\n" #define P pair vector

v[500005]; struct BipartiteMatching { vector< vector< int > > graph; vector< int > match, alive, used; int timestamp; BipartiteMatching(int n) : graph(n), alive(n, 1), used(n, 0), match(n, -1), timestamp(0) {} void add_edge(int u, int v) { graph[u].push_back(v); graph[v].push_back(u); } bool dfs(int idx) { used[idx] = timestamp; for (auto &to : graph[idx]) { int to_match = match[to]; if (alive[to] == 0) continue; if (to_match == -1 || (used[to_match] != timestamp && dfs(to_match))) { match[idx] = to; match[to] = idx; return true; } } return false; } int bipartite_matching() { int ret = 0; for (int i = 0; i < graph.size(); i++) { if (alive[i] == 0) continue; if (match[i] == -1) { ++timestamp; ret += dfs(i); } } return ret; } void output() { for (int i = 0; i < graph.size(); i++) { if (i < match[i]) { cout << i << "-" << match[i] << endl; } } } }; int main() { ios::sync_with_stdio(false); cin.tie(nullptr); int h, w; cin >> h >> w; rep(i, h) rep(j, w) { int a; cin >> a; v[a].push_back({ i,j }); } int ans = 0; rep(i, 50000) { if (0 == i) continue; if (v[i].empty()) continue; setst; for (auto p : v[i]) { st.insert(p.first); st.insert(p.second + h); } mapmp; for (auto s : st) { mp[s] = mp.size(); } //二部グラフの二部グラフの最大マッチング = 最小頂点被覆 BipartiteMatching g(mp.size()); for (auto p : v[i]) { g.add_edge(mp[p.first], mp[p.second + h]); } ans += g.bipartite_matching(); } cout << ans << endl; return 0; }