#include using namespace std; typedef signed long long ll; #define _P(...) (void)printf(__VA_ARGS__) #define FOR(x,to) for(x=0;x<(to);x++) #define FORR(x,arr) for(auto& x:arr) #define FORR2(x,y,arr) for(auto& [x,y]:arr) #define ALL(a) (a.begin()),(a.end()) #define ZERO(a) memset(a,0,sizeof(a)) #define MINUS(a) memset(a,0xff,sizeof(a)) 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;} //------------------------------------------------------- template class MaxFlow_dinic { public: struct edge { int to,reve;V cap;}; static const int MV = 20202; vector E[MV]; int itr[MV],lev[MV],mincut[MV]; //1ならsource側 void add_edge(int x,int y,V cap,bool undir=false) { E[x].push_back((edge){y,(int)E[y].size(),cap}); E[y].push_back((edge){x,(int)E[x].size()-1,undir?cap:0}); } void bfs(int cur) { MINUS(lev); queue q; lev[cur]=0; q.push(cur); while(q.size()) { int v=q.front(); q.pop(); FORR(e,E[v]) if(e.cap>0 && lev[e.to]<0) lev[e.to]=lev[v]+1, q.push(e.to); } } V dfs(int from,int to,V cf) { if(from==to) return cf; for(;itr[from]cap>0 && lev[from]to]) { V f=dfs(e->to,to,min(cf,e->cap)); if(f>0) { e->cap-=f; E[e->to][e->reve].cap += f; return f; } } } return 0; } V maxflow(int from, int to) { V fl=0,tf; while(1) { bfs(from); if(lev[to]<0) break; ZERO(itr); while((tf=dfs(from,to,numeric_limits::max()))>0) fl+=tf; } //最小カット復元 ZERO(mincut); queue Q; mincut[from]=1; Q.push(from); while(Q.size()) { int cur=Q.front(); Q.pop(); FORR(e,E[cur]) if(e.cap>0&&mincut[e.to]==0) mincut[e.to]=1, Q.push(e.to); } return fl; } }; int N,M; MaxFlow_dinic mf; int E[5050]; void solve() { int i,j,k,l,r,x,y; string s; cin>>N>>M; FOR(i,N) mf.add_edge(2*N,i,1); FOR(i,N) mf.add_edge(i+N,2*N+1,1); FOR(i,M) { cin>>x>>y; mf.add_edge(x-1,N+y-1,1); mf.add_edge(y-1,N+x-1,1); E[x-1]++; E[y-1]++; } x=mf.maxflow(2*N,2*N+1); int ret=2*x-N; if(x==N-1) { FOR(i,N) if(E[i]==0) ret-=2; } cout<