#include #define PPque priority_queue, vector>, greater>> #define Pque priority_queue, vector>, greater>> #define pque priority_queue, greater> #define umap unordered_map #define uset unordered_set #define rep(i, s, f) for(ll i = s; i <= f; i++) #define per(i, s, f) for(ll i = s; i >= f; i--) #define all0(x) (x).begin() ,(x).end() #define all(x) (x).begin() + 1, (x).end() #define vvvi vector>> #define vvvl vector>> #define vvvc vector>> #define vvvd vector>> #define vvvm vector>> #define vvi vector> #define vvl vector> #define vvs vector> #define vvc vector> #define vvp vector>> #define vvb vector> #define vvd vector> #define vvm vector> #define vp vector> #define vi vector #define vl vector #define vs vector #define vc vector #define vb vector #define vd vector #define vm vector #define P pair #define TU tuple #define rrr(l, r) mt()%(r-l+1)+l #define ENDL '\n' #define ull unsigned long long typedef long long ll; using namespace std; //////////////////////////////////////////////////////////////////////////////////////////////////////////// //これが本当の組み込み関数ってね(笑) template T or_less(vector &A, T x) { //x以下で最大要素の添字 前提: sort済み 存在しない: -1 return distance(A.begin(), upper_bound(A.begin(), A.end(), x)-1); } template T under(vector &A, T x) { //x未満の最大要素の添字 前提: sort済み 存在しない: -1 return distance(A.begin(), lower_bound(A.begin(), A.end(), x)-1); } template T or_more(vector &A, T x) { //x以上で最小要素の添字  前提: sort済み 存在しない: N . //distanceのA.beginは添字を出すために常にA.begin() NG: A.begin() + 1 return distance(A.begin(), lower_bound(A.begin(), A.end(), x)); } template T over(vector &A, T x) { //xより大きい最小要素の添字前提: sort済み 存在しない: N return distance(A.begin(), upper_bound(A.begin(), A.end(), x)); } void compress(vector &A) {//小さい順に順位、大きい順にしたいならreverseはNG最後に変換 vector temp = A; sort(temp.begin()+1, temp.end()); for (int i = 1; i <= int(A.size()-1); i++) { A.at(i) = distance(temp.begin(), lower_bound(temp.begin()+1, temp.end(), A.at(i))); } } ////////////////////////////////////////////////////////////////////// //数学系 /////////////////////////////////////////////////////////////////////// ll round(ll x, ll i) {return ll(x + 5 * pow(10, i-1))/ll(pow(10, i)) * ll(pow(10, i));} ll nto10(string S, ll base) { ll res = 0; reverse(all0(S)); while(!S.empty()) { ll num = S.back() - '0'; if(num < 0 || num > 9) num = 9 + S.back() - 'a' + 1; res = res * base + num; S.pop_back(); } return res; } string toN(ll N, ll base) { if(N == 0) return "0"; string ans =""; ll MOD = abs(base); while(N != 0) { ll first = N % MOD; while(first < 0) first += MOD; ans += to_string(first); N -= first; N /= base; } reverse(all0(ans)); return ans; } vp insu_bunkai(ll N) { vp res; for (int i = 2; i * i <= N; i++) { ll cnt = 0; while(N % i == 0) { cnt++; N /= i; } if(cnt != 0) res.push_back(P(i, cnt)); } if(N != 1) res.push_back(P(N, 1)); return res; } struct comb_fast {//must素数 vl fac; vl facinv; vl inv; ll mod_comb; comb_fast (ll n, ll mod) { mod_comb = mod; fac.assign(n+1, 1); facinv.assign(n+1, 1); inv.assign(n+1, 1); rep(i, 2, n) { fac.at(i) = fac.at(i-1) * i % mod_comb; inv.at(i) = mod_comb - inv.at(mod_comb%i) * (mod_comb/i)%mod_comb; facinv.at(i) = facinv.at(i-1) * inv.at(i) % mod_comb; } } ll get(ll n, ll k) { if(n < k) return 0; if(n < 0 || k < 0) return 0; return fac.at(n) * (facinv.at(k) * facinv.at(n-k)%mod_comb)%mod_comb; } }; vvl comb_slow(ll n, ll mod) {//計算にO(N^2) 読み取りにO(1) vvl v(n+1, vl(n+1, 0)); rep(i, 0, v.size() - 1) {v.at(i).at(0) = 1;v.at(i).at(i) = 1;} rep(i, 1, v.size()-1) { rep(j, 1, i) { v.at(i).at(j) = v.at(i-1).at(j-1) + v.at(i-1).at(j);v.at(i).at(j) %= mod;}} return v; } double KAKUDO(double rad){return rad * 180 / 3.141592653589793;} double RAD(double kakudo) {return kakudo / 180 * 3.141592653589793;} ll extgcd (ll a, ll b, ll &x, ll &y) { if(b == 0) { x = 1;y = 0;return a;} ll d = extgcd(b, a%b, y, x); y -= a/b * x; return d; } template T ceil(T a, T b) { assert(b != 0); if(a % b == 0) return a / b; if((a <= 0 && b < 0) || (a >= 0 && b > 0)) return a/b + 1; else return a / b; } template T floor(T a, T b) { assert(b != 0); if(a % b == 0) return a / b; if((a <= 0 && b < 0) || (a >= 0 && b > 0)) return a/b; else return a/b - 1; } ////////////////////////////////////////////////////////////////////////////////////////////////////////////// ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// //グローバル変数を置くところ(情報工学意識高め) //#pragma GCC optimize("O3") //#pragma GCC optimize("unroll-loops") ll int_max = 1001001001; ll ll_max = 1001001001001001001LL; const double pi = 3.141592653589793; vl dx{0, 1, 0, -1, 0, 1, 1, -1, -1};//右から時計回り vl dy{0, 0, -1, 0, 1, 1, -1, -1, 1}; //#pragma GCC optimize ("-O3") //const ll mod = 1000000007; //const ll mod = 998244353; ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// void solve() { ll N, M; cin >> N >> M; vector> G(N+1, multiset()); rep(i, 1, M) { ll u, v; cin >> u >> v; G.at(u).insert(v); } auto dfs = [&](auto dfs, ll now, set & visited) -> ll { if(visited.count(now)) { return now; } if(G.at(now).empty()) return -1; visited.insert(now); auto itr = G.at(now).begin(); while(itr != G.at(now).end()) { ll d = dfs(dfs, *itr, visited); if(d != -1) { G.at(now).erase(itr++); if(d != now) { visited.erase(now); return d; } else continue; } else { itr++; } } visited.erase(now); return -1; }; rep(i, 1, N) { set visited; dfs(dfs, i, visited); } ll cnt = 0; rep(i,1, N) { for(auto to : G.at(i)) { cnt++; } } cout << N << " " << cnt << endl; rep(i,1, N) { for(auto to : G.at(i)) { cout << i << " "<< to << endl; } } } //座標を2で割った時の”切り捨て側(左側)”を求めるには 誤:(x / 2) マイナスの時!!! 正:floor(x, 2); //stringでの数字の下から1桁目は 正:S.at(N-1) 誤:S.at(0) //if(S.at(i) == 1 ← charなのに1...? // modは取りましたか...?(´・ω・`) int main() { ios::sync_with_stdio(false); std::cin.tie(nullptr); cout << fixed << setprecision(15); solve(); return 0; }