#include<bits/stdc++.h>
#define ll long long
using namespace std;
const int MAXN=2e5+5,MOD=1e9+7;
ll fac[MAXN];
vector <int> G[MAXN],ve[MAXN];
vector <array<int,2>> edg[MAXN];
unordered_set <int> E[MAXN];
int dfn[MAXN],low[MAXN],dcnt,stk[MAXN],tp,tot;
bool ins[MAXN];
int deg[MAXN<<1],fa[MAXN<<1];
void tarjan(int u) {
	dfn[u]=low[u]=++dcnt,ins[stk[++tp]=u]=true;
	for(int v:G[u]) {
		if(!dfn[v]) {
			tarjan(v),low[u]=min(low[u],low[v]);
			if(low[v]>=dfn[u]) {
				fa[++tot]=u;
				while(ins[v]) fa[stk[tp]]=tot,ins[stk[tp--]]=false;
			}
		} else low[u]=min(low[u],dfn[v]);
	}
}
signed main() {
	for(int i=fac[0]=1;i<MAXN;++i) fac[i]=fac[i-1]*i%MOD;
	int n,m;
	scanf("%d%d",&n,&m);
	for(int i=1,u,v;i<=m;++i) scanf("%d%d",&u,&v),G[u].push_back(v),G[v].push_back(u);
	tot=n,tarjan(1);
	for(int i=1;i<=tot;++i) if(fa[i]) ++deg[fa[i]],++deg[i];
	for(int i=1;i<=n;++i) if(fa[i]) ve[fa[i]-n].push_back(i);
	for(int i=n+1;i<=tot;++i) if(fa[i]) ve[i-n].push_back(fa[i]);
	for(int i=1;i<=n;++i) for(int j:G[i]) if(j<i) {
		edg[fa[(fa[fa[i]]==j?i:j)]-n].push_back({i,j});
	}
	for(int i=1;i<=tot-n;++i) {
		for(int u:ve[i]) E[u].clear();
		queue <int> q;
		for(auto e:edg[i]) E[e[0]].insert(e[1]),E[e[1]].insert(e[0]);
		for(int u:ve[i]) if(E[u].size()==2) q.push(u);
		while(q.size()) {
			int u=q.front(); q.pop();
			if(E[u].size()!=2) continue;
			int x=*E[u].begin(),y=*++E[u].begin();
			E[x].erase(u),E[y].erase(u),E[u].clear();
			if(!E[x].count(y)) E[x].insert(y),E[y].insert(x);
			if(E[x].size()==2) q.push(x);
			if(E[y].size()==2) q.push(y);
		}
		int c=0;
		for(int u:ve[i]) c+=!E[u].empty();
		if(c!=2) return puts("0"),0;
	}
	ll ans=n;
	for(int i=1;i<=n;++i) ans=ans*fac[deg[i]]%MOD;
	for(int i=n+1;i<=tot;++i) if(deg[i]>2) ans=ans*2%MOD;
	printf("%lld\n",ans);
	return 0;
}