/* Contest: - Problem: Yukicoder 1116 Author: tzc_wk Time: 2020.8.17 */ #include using namespace std; #define fi first #define se second #define pb push_back #define fz(i,a,b) for(int i=a;i<=b;i++) #define fd(i,a,b) for(int i=a;i>=b;i--) #define foreach(it,v) for(__typeof(v.begin()) it=v.begin();it!=v.end();it++) #define all(a) a.begin(),a.end() #define fill0(a) memset(a,0,sizeof(a)) #define fill1(a) memset(a,-1,sizeof(a)) #define fillbig(a) memset(a,0x3f,sizeof(a)) #define y1 y1010101010101 #define y0 y0101010101010 typedef pair pii; typedef long long ll; inline int read(){ int x=0,neg=1;char c=getchar(); while(!isdigit(c)){ if(c=='-') neg=-1; c=getchar(); } while(isdigit(c)) x=x*10+c-'0',c=getchar(); return x*neg; } int n=read(),m=read(); const ll MOD=998244353; const ll MAGIC=499122177; ll p2[100005],fac[100005],inv[100005]; ll qpow(ll x,int e){ ll ans=1;while(e){if(e&1) ans=ans*x%MOD;x=x*x%MOD;e>>=1;} return ans; } inline void prework(){ p2[0]=1;for(int i=1;i<=n;i++) p2[i]=p2[i-1]*2ll%MOD; fac[0]=1;for(int i=1;i<=n;i++) fac[i]=fac[i-1]*i%MOD; for(int i=0;i<=n;i++) inv[i]=qpow(fac[i],MOD-2); } inline ll getc(int x,int y){ return fac[x]*inv[y]%MOD*inv[x-y]%MOD; } inline ll geta(int x,int y){ return fac[x]*inv[x-y]%MOD; } struct edge{ int u,v; } e[16]; int key[32],hs[32],cnt=0,num=0; int f[32],deg[32],siz[32]; inline int find(int x){ return (f[x]==x)?x:f[x]=find(f[x]); } ll dp[100005][16]; inline ll solve(int msk){ fill0(deg);fill0(f);fill0(siz);fz(i,1,num) f[i]=i,siz[i]=1; int cyc=0; for(int i=1;i<=m;i++){ if(msk>>(i-1)&1){ int x=e[i].u,y=e[i].v; deg[x]++;deg[y]++; x=find(x);y=find(y); if(x!=y) f[y]=x,siz[x]+=siz[y]; else cyc++; } } for(int i=1;i<=num;i++) if(deg[i]>2) return 0; int one=0,chain=0,chain_siz=0; for(int i=1;i<=num;i++) if(find(i)==i){ if(siz[i]>1) chain++,chain_siz=siz[i]; else one++; } one+=n-num; // cout<=2) return 0; if(cyc==1&&chain>1) return 0; if(cyc==1&&chain==1) return 1; if(chain==0){ ll ans=0; for(int i=3;i<=n;i++) ans=(ans+getc(n,i)*fac[i-1]%MOD*MAGIC%MOD)%MOD; return ans; } ll ans=fac[chain-1]*p2[chain-1]%MOD*dp[one][chain]%MOD; if(chain==1&&chain_siz==2) ans--; if(ans<0) ans+=MOD; return ans; } inline ll count(int x){return (__builtin_popcount(x)%2)?-1ll:1ll;} int main(){ prework(); for(int i=n;i>=max(n-30,0);i--){ for(int j=1;j<=min(n,15);j++){ if(i+j>n) continue; for(int k=0;k<=i;k++) dp[i][j]=(dp[i][j]+getc(k+j-1,j-1)*geta(i,k)%MOD)%MOD; } } // puts("IN"); for(int i=1;i<=m;i++) e[i].u=read(),e[i].v=read(); for(int i=1;i<=m;i++) key[++cnt]=e[i].u,key[++cnt]=e[i].v; sort(key+1,key+cnt+1); for(int i=1;i<=cnt;i++) if(key[i]!=key[i-1]) hs[++num]=key[i]; for(int i=1;i<=m;i++) e[i].u=lower_bound(hs+1,hs+num+1,e[i].u)-hs; for(int i=1;i<=m;i++) e[i].v=lower_bound(hs+1,hs+num+1,e[i].v)-hs; ll ans=0; for(int i=0;i<(1<