#include <iostream>
#include <cstdio>
#include <cstring>
#define mod 1000000007
using namespace std;
void inc(int &x,int y){
	x+=y;
	if (x>=mod)x-=mod;
	return;
}
int n,u[1005],v[1005],first[1005],nxt[1005];
int fac[85],C[85][85];
int sz[85],f[85][85],g[85][85][85][2];
int tot,c[85];
void dfs(int now,int fa){
	sz[now]=1;
	for (int i=first[now];i;i=nxt[i])
		if (v[i]!=fa){
			dfs(v[i],now);
			sz[now]+=sz[v[i]];
		}
	tot=0;
	for (int i=first[now];i;i=nxt[i])
		 if (v[i]!=fa)c[++tot]=v[i];
	memset(g,0,sizeof(g));
	g[0][0][1][0]=g[0][0][1][1]=g[0][1][0][0]=1;
	int s=1;
	for (int i=0;i<tot;i++){
		int t=sz[c[i+1]];
		for (int j=0;j<=s;j++)
			for (int k=0;j+k<=s;k++){
				for (int l=0;l<=t;l++){
					if (l==t){
						inc(g[i+1][j+l][k][0],g[i][j][k][0]);
						inc(g[i+1][j+l][k][1],g[i][j][k][1]);
					}
					for (int p=1;p<=t-l;p++){
						int qwq=1ll*C[t][l]*fac[t-l]%mod*C[t-l-1][p-1]%mod;
						if (((t-l)-p)&1)qwq=(mod-qwq)%mod;
						inc(g[i+1][j+l][k+p][0],1ll*qwq*C[k+p][p]%mod*g[i][j][k][0]%mod);
						inc(g[i+1][j+l][k+p][1],1ll*qwq*C[k+p-1][p]%mod*g[i][j][k][1]%mod);
						for (int q=1;q<=t-l-p+1;q++){
							int qwq=f[c[i+1]][t-q];
							qwq=1ll*qwq*C[t-q][l]%mod*fac[t-l-q]%mod*C[t-l-q][p-1]%mod;
							if (((t-l-q+1)-p)&1)qwq=(mod-qwq)%mod;
							inc(g[i+1][j+l][k+p][1],1ll*qwq*C[k+p-1][p-1]%mod*g[i][j][k][0]%mod);
						}
					}
				}
			}
		s+=t;
	}
	for (int i=0;i<=s;i++)
		for (int j=1;j<=s;j++)
			inc(f[now][i],g[tot][i][j][1]);
	f[now][s]=1;
	return;
}
int main(){
	cin>>n;
	for (int i=1;i<=n;i++){
		cin>>u[i]>>v[i];
		nxt[i]=first[u[i]],first[u[i]]=i;
		u[i+n]=v[i],v[i+n]=u[i];
		nxt[i+n]=first[u[i+n]],first[u[i+n]]=i+n;
	}
	fac[0]=1;
	for (int i=1;i<=n;i++)fac[i]=1ll*fac[i-1]*i%mod;
	for (int i=0;i<=n;i++)C[i][0]=1;
	for (int i=1;i<=n;i++)
		for (int j=1;j<=i;j++)
			C[i][j]=(C[i-1][j-1]+C[i-1][j])%mod;
	dfs(1,0);
	cout<<f[1][0]<<endl;
	return 0;
}