20241225代码：

#include<bits/stdc++.h>
using namespace std;
const int N=1e3+10;
vector<pair<int,int>>G[N];int cut[N],root;vector<int> vdcc[N];
int tsp,cnt,dfn[N],low[N];
stack<int>stk;bool instk[N];
void tarjan(int x,int in_id)
{
	dfn[x]=low[x]=++tsp;
	if(G[x].size()==0){vdcc[++cnt].push_back(x);return ;}
	
	stk.push(x);instk[x]=1;
	int child=0;
	for(auto i:G[x])if(i.second!=in_id)
	{
		int y=i.first,id=i.second;
		if(dfn[y]==0)
		{
			tarjan(y,id);
			low[x]=min(low[x],low[y]);
			if(dfn[x]<=low[y])
			{
				child++;
				if(x!=root || child>1)cut[x]=1;
				cnt++;
				for(int z=-1;z!=y;)
				{
					z=stk.top();stk.pop();instk[z]=0;
					vdcc[cnt].push_back(z); 
				};
				vdcc[cnt].push_back(x);
			}
		}
		else if(instk[y]==1)low[x]=min(low[x],dfn[y]);
	}
}
int main()
{
	int n,m,T=0;
	while(scanf("%d",&m)!=EOF && m)
	{
		n=0;
        memset(G,0,sizeof(G));
		for(int i=1,x,y;i<=m;i++)
		{
			scanf("%d%d",&x,&y);
            G[x].push_back({y,i});
            G[y].push_back({x,i});
			n=max({n,x,y});
		}
		tsp=cnt=0;memset(dfn,0,sizeof(dfn));memset(low,0,sizeof(low));memset(cut,0,sizeof(cut));
		memset(instk,0,sizeof(instk));memset(vdcc,0,sizeof(vdcc));
		for(int i=1;i<=n;i++)if(dfn[i]==0)root=i,tarjan(i,0);
	
		int sum=0;
		unsigned long long ans=1;
		for(int i=1;i<=cnt;i++)
		{
			int t=0,cn=vdcc[i].size();
			for(int j:vdcc[i])if(cut[j])t++;
			if(t==0)
			{
				if(cn>1)sum+=2,ans=ans*cn*(cn-1)/2;
				else sum++;
			}
			else if(t==1)sum++,ans=ans*(cn-1);
		} 
		printf("Case %d: %d %llu\n",++T,sum,ans);
	}
    return 0;
}