#include #include #define rep(i,n) for (int i = 0; i < int(n); ++i) #define repp(i,n,m) for (int i = m; i < int(n); ++i) #define reb(i,n) for (int i = int(n)-1; i >= 0; --i) #define all(v) v.begin(),v.end() using namespace std; using namespace atcoder; using ll = long long; using ull = unsigned long long; using ld = long double; using P = pair; using PL = pair; using pdd = pair; using pil = pair; using pli = pair; templateistream &operator>>(istream &is,vector &v){for(auto &e:v)is>>e;return is;} templatebool range(T a,T b,T x){return (a<=x&&xbool rrange(T a,T b,T c,T d,T x,T y){return (range(a,c,x)&&range(b,d,y));} template T rev(const T& str_or_vec){T res = str_or_vec; reverse(res.begin(),res.end()); return res; } templatebool chmin(T &a,const T &b){if(a>b){a=b;return true;}return false;} templatebool chmax(T &a,const T &b){if(avoid uniq(vector &v){sort(v.begin(),v.end());v.erase(unique(v.begin(),v.end()),v.end());} templatevoid print(pair a); templatevoid print(vector v); templatevoid print(vector> v); void print(){ putchar(' '); } void print(bool a){ printf("%d", a); } void print(int a){ printf("%d", a); } void print(long a){ printf("%ld", a); } void print(long long a){ printf("%lld", a); } void print(char a){ printf("%c", a); } void print(char a[]){ printf("%s", a); } void print(const char a[]){ printf("%s", a); } void print(long double a){ printf("%.15Lf", a); } void print(const string& a){ for(auto&& i : a) print(i); } void print(unsigned int a){ printf("%u", a); } void print(unsigned long long a) { printf("%llu", a); } template void print(const T& a){ cout << a; } int out(){ putchar('\n'); return 0; } template int out(const T& t){ print(t); putchar('\n'); return 0; } template int out(const Head& head, const Tail&... tail){ print(head); putchar(' '); out(tail...); return 0; } templatevoid print(pair a){print(a.first);print(),print(a.second);} templatevoid print(vector v){for(auto ite=v.begin();ite!=v.end();){print(*ite);if(++ite!=v.end())print();}} templatevoid print(vector> v){for(auto ite=v.begin();ite!=v.end();){print(*ite);if(++ite!=v.end())out();}} void yes(){out("Yes");} void no (){out("No");} void yn (bool t){if(t)yes();else no();} void fast_io(){cin.tie(0); ios::sync_with_stdio(0); cout< dx = {0,1,0,-1,1,1,-1,-1}; const vector dy = {1,0,-1,0,1,-1,-1,1}; const string ALP = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"; const string alp = "abcdefghijklmnopqrstuvwxyz"; const string NUM = "0123456789"; } // namespace noya2 using namespace noya2; using mint = modint998244353; //using mint = modint1000000007; //using mint = modint; void out(mint a){out(a.val());} void out(vector a){vector b(a.size()); rep(i,a.size()) b[i] = a[i].val(); out(b);} void out(vector> a){for (auto v : a) out(v);} void solve(){ int n, m; cin >> n >> m; int s = 2*n, t = s+1; mf_graph g(t+1); vector a(n); rep(i,m){ int u, v; cin >> u >> v; u--, v--; g.add_edge(u,n+v,1); g.add_edge(v,n+u,1); a[u]++, a[v]++; } vector ids(n); rep(i,n){ g.add_edge(s,i,1); ids[i] = g.add_edge(n+i,t,1); } int ans = g.flow(s,t); bool ng = false; if (ans == n-1){ rep(i,n){ if (g.get_edge(ids[i]).flow == 0 && a[i] == 0) ng = true; } } out(2*ans - n - (ng ? 2 : 0)); } int main(){ fast_io(); int t = 1; //cin >> t; while(t--) solve(); }