#include<bits/stdc++.h>
#define Gc() getchar()
#define Me(x,y) memset(x,y,sizeof(x))
#define Mc(x,y) memcpy(x,y,sizeof(x))
#define d(x,y) ((m)*(x-1)+(y))
#define R(n) (rnd()%(n)+1)
#define Pc(x) putchar(x)
#define LB lower_bound
#define UB upper_bound
#define fi first
#define se second
#define eb emplace_back
using namespace std;using ll=long long;using db=double;using lb=long db;using ui=unsigned;using ull=unsigned long long;using pii=pair<int,int>;
const int N=600+5,M=200+5,K=(1<<25)+5,mod=1e9+7,Mod=mod-1;const db eps=1e-9;const int INF=1e9+7;mt19937 rnd(time(0));
int n,m;vector<pii> S[N];
int x[N*2],y[N*2],cnt=-1;
void con(int u,int v){
	S[u].emplace_back(v,++cnt);x[cnt]=u;y[cnt]=v;//cerr<<u<<' '<<v<<' '<<cnt<<'\n';
	S[v].emplace_back(u,++cnt);x[cnt]=v;y[cnt]=u;//cerr<<v<<' '<<u<<' '<<cnt<<'\n';
}
int rt,r1,r2,d1[N],d2[N],len;ll C[N][N],frc[N],inv[N];
void dfs(int x,int La,int *d){
	d[x]=d[La]+1;if(d[x]>d[r1]) r1=x;
	for(auto i:S[x]) if(i.fi^La) dfs(i.fi,x,d);
}
int s1[N][N],s2[N*2][N],d[N][N];
ll f[N*2][N],g[N*2][N];
void Solve(){
	int i,j,h;scanf("%d",&n);if(n==1){puts("1");return;}
	for(i=1;i<n;i++) {int x,y;scanf("%d%d",&x,&y);con(x,i+n);con(y,i+n);}
	r1=1;dfs(1,0,d1);r2=r1;dfs(r1,0,d2);r2=r1;dfs(r1,0,d1);len=(d1[r1]-1)/2;
	for(i=1;i<=2*n;i++) if(d1[i]==len+1&&d2[i]==len+1) rt=i;
	for(i=0;i<=n;i++) for(C[i][0]=j=1;j<=i;j++) C[i][j]=(C[i-1][j]+C[i-1][j-1])%mod;
	inv[1]=1;for(i=2;i<=n;i++) inv[i]=(mod-inv[mod%i])*(mod/i)%mod;
	for(frc[0]=inv[0]=i=1;i<=n;i++) frc[i]=frc[i-1]*i%mod,inv[i]=inv[i-1]*inv[i]%mod;
	for(i=1;i<2*n;i++) dfs(i,0,d[i]);
	for(i=1;i<2*n;i++){
		for(j=1;j<2*n;j++) if(d[i][j]-1<=len) s1[d[i][j]-1][i]++;
		for(auto o:S[i]) for(j=1;j<2*n;j++) if(d[i][j]-1<=len&&d[o.fi][j]==d[i][j]-1) s2[d[i][j]-1][o.se]++;
	}
	cerr<<s1[2][2]<<'\n';
	int cts=0;
	for(i=len;i;i--){
		int *sz1=s1[i],*sz2=s2[i];
		if(i==len)for(j=0;j<=cnt;j++) if(x[j]==rt){f[j][sz1[x[j]]-sz2[j]]=1;break;}
		for(j=0;j<=cnt;j++)if((x[j]<=n)^(i&1)){
			int u=x[j],v=y[j];
			for(h=1;h<=sz1[u]-sz2[j];h++)if(f[j][h]){//cerr<<j<<' '<<h<<'\n';
				for(int p=1;p<=sz2[j];p++){
					ll w=f[j][h];
					w=w*C[h-1+sz2[j]-p][h-1]%mod*frc[sz1[u]-sz2[j]]%mod;
					f[j^1][p]=(f[j^1][p]+w)%mod;
				}
				for(auto o:S[u]) if(o.se^j){
					for(int p=1;p<=h&&p<=sz2[o.se];p++){
						ll w1=C[h-p+sz2[j]][sz2[j]]*C[sz1[u]-p-sz2[j]][sz1[u]-sz2[o.se]-sz2[j]]%mod;
						ll w2=C[h-p-1+sz2[j]][sz2[j]]*C[sz1[u]-p-sz2[j]-1][sz1[u]-sz2[o.se]-sz2[j]]%mod;
						// cerr<<w1<<' '<<w2<<'\n';
						ll w=f[j][h]*(w1-w2+mod)%mod*frc[sz2[j]]%mod*frc[sz1[u]-sz2[o.se]-sz2[j]]%mod;
						// cerr<<w<<'\n';
						f[o.se^1][p]=(f[o.se^1][p]+w)%mod;
					}
				}
				f[j][h]=0;
			}
		}
	}
	cerr<<cts<<'\n';
	ll tot=0;for(i=0;i<=cnt;i++) tot+=f[i][1];printf("%lld\n",tot%mod);
}
int main(){
	int t=1;
	// scanf("%d",&t);
	while(t--) Solve();
	cerr<<clock()*1.0/CLOCKS_PER_SEC<<'\n';
}