#include #include using namespace std; const long mod=998244353; long power(long a,long b){return b?power(a*a%mod,b/2)*(b%2?a:1)%mod:1;} long fac[1<<17],inv[1<<17]; long comb(int N,int K){return fac[N]*inv[K]%mod*inv[N-K]%mod;} int N,M; int a[15],b[15]; map,long>memo; main() { cin>>N>>M; for(int i=0;i>a[i]>>b[i]; fac[0]=1; for(int i=1;i<=N;i++)fac[i]=fac[i-1]*i%mod; inv[N]=power(fac[N],mod-2); for(int i=N;i--;)inv[i]=inv[i+1]*(i+1)%mod; long ans=0; for(int k=3;k<=N;k++) { (ans+=comb(N,k)*fac[k-1]%mod)%=mod; } for(int i=1;i<1<mp; bool ok=true; int one=0,edge=0; for(int j=0;j>j&1) { edge++; if(mp[a[j]]==2) { ok=false; break; } else if(mp[a[j]]==1) { mp[a[j]]=2; one--; } else { mp[a[j]]=1; one++; } if(mp[b[j]]==2) { ok=false; break; } else if(mp[b[j]]==1) { mp[b[j]]=2; one--; } else { mp[b[j]]=1; one++; } } if(!ok)continue; int m=mp.size(); long now; pairp=make_pair(m,one); if(memo.find(p)!=memo.end())now=memo[p]; else { now=0; for(int k=0;k<=N-m;k++) { if(m+k>=3)(now+=comb(N-m,k)*fac[k+one/2-1]%mod)%=mod; } now=now*power(2,one/2)%mod; if(one==0)now=2; memo[p]=now; } if(edge%2==1)ans=(ans+mod-now)%mod; else ans=(ans+now)%mod; } cout<