#include using namespace std; #define REP(i,n) for(ll i=0;i<(ll)n;i++) #define dump(x) cerr << #x << " = " << (x) << endl; #define spa << " " << #define fi first #define se second #define ALL(a) (a).begin(),(a).end() #define ALLR(a) (a).rbegin(),(a).rend() using ld = long double; using ll = long long; using ull = unsigned long long; using pii = pair; using pll = pair; using pdd = pair; template struct V : vector { using vector::vector; }; V() -> V; V(size_t) -> V; template V(size_t, T) -> V; template vector make_vec(size_t n, T a) { return vector(n, a); } template auto make_vec(size_t n, Ts... ts) { return vector(n, make_vec(ts...)); } template ostream& operator << (ostream& os, const pair v){os << "(" << v.first << ", " << v.second << ")"; return os;} template ostream& operator<<(ostream &os, const vector &v) { for (auto &e : v) os << e << ' '; return os; } template ostream& operator<<(ostream& os, const vector> &v){ for(auto &e : v){os << e << "\n";} return os;} struct fast_ios { fast_ios(){ cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(20); }; } fast_ios_; template bool chmax(T &a, const T &b) { if (a bool chmin(T &a, const T &b) { if (a>b) { a=b; return 1; } return 0; } void fail() { cout << -1 << '\n'; exit(0); } inline int popcount(const int x) { return __builtin_popcount(x); } inline int popcount(const ll x) { return __builtin_popcountll(x); } template void debug(vector>&v,ll h,ll w){for(ll i=0;i void debug(vector&v,ll n){if(n!=0)cerr<>; template< typename G > struct StronglyConnectedComponents { const G &g; Graph gg, rg; vector< int > comp, order, used; StronglyConnectedComponents(G &g) : g(g), gg(g.size()), rg(g.size()), comp(g.size(), -1), used(g.size()) { for(int i = 0; i < (int)g.size(); i++) { for(auto e : g[i]) { gg[i].emplace_back((int) e); rg[(int) e].emplace_back(i); } } } int operator[](int k) { return comp[k]; } void dfs(int idx) { if(used[idx]) return; used[idx] = true; for(int to : gg[idx]) dfs(to); order.push_back(idx); } void rdfs(int idx, int cnt) { if(comp[idx] != -1) return; comp[idx] = cnt; for(int to : rg[idx]) rdfs(to, cnt); } void build(Graph &t) { for(int i = 0; i < (int)gg.size(); i++) dfs(i); reverse(begin(order), end(order)); int ptr = 0; for(int i : order) if(comp[i] == -1) rdfs(i, ptr), ptr++; t.resize(ptr); for(int i = 0; i < (int)g.size(); i++) { for(auto &to : g[i]) { int x = comp[i], y = comp[to]; if(x == y) continue; t[x].push_back(y); } } } }; int main(){ ll N, M; cin >> N >> M; ll res = 0; res += N * (N+1) / 2; V B(M), C(M); REP(i, M){ cin >> B[i] >> C[i]; } set st; REP(i, M){ st.insert(B[i]); st.insert(C[i]); } map mp; ll cnt = 0; V score; for(auto x: st){ mp[x] = cnt; score.push_back(x); cnt++; res -= x; } ll K = cnt; Graph G(K), T; REP(i, M){ G[mp[B[i]]].push_back(mp[C[i]]); } for(auto &v: G){ sort(ALL(v)); v.erase(unique(ALL(v)), v.end()); } StronglyConnectedComponents scc(G); scc.build(T); ll S = T.size(); for(auto &v: T){ sort(ALL(v)); v.erase(unique(ALL(v)), v.end()); } V ma(S, 0), sz(S, 0); REP(i, K){ chmax(ma[scc[i]], score[i]); sz[scc[i]]++; } V dp(S, -1); // dump(S) auto rec = [&](auto self, ll now){ if(dp[now]>=0) return dp[now]; ll val = ma[now]; for(auto next: T[now]){ ll tmp = self(self, next); chmax(val, tmp); } dp[now] = val; res += val * sz[now]; return val; }; REP(i, S) rec(rec, i); cout << res << endl; return 0; }