#include<bits/stdc++.h>
using namespace std;
const int MAXN = 610,M = 3000,mod = 1e9+7;
int addv(int x,int y){return (x+y>=mod) ? (x+y-mod) : (x+y);}
int subv(int x,int y){return (x>=y) ? (x-y) : (x-y+mod);}
void add(int& x,int y){x = addv(x,y);}
void sub(int& x,int y){x = subv(x,y);}
int qpow(int a,int n){
    int res = 1; a%=mod;
    while(n){
        if(n&1)res = 1ll*res*a%mod;
        n>>=1; a = 1ll*a*a%mod;
    }
    return res;
}
int qinv(int a){return qpow(a,mod-2);}
//
typedef array<int,4> qr; typedef vector<int> vec;

int n,rn,r,len,C[M+10][M+10],fac[M+10];
vector<int> e[MAXN];

void link(int u,int v){e[u].push_back(v); e[v].push_back(u);}

int f[MAXN][MAXN],g[MAXN][MAXN],up[MAXN][MAXN],dfn[MAXN],sz[MAXN],dtot;
int chk(int x,int y){return dfn[x]<=dfn[y]&&dfn[x]+sz[x]>dfn[y];}

int id[MAXN][MAXN],ic;
bool vis[MAXN*2][MAXN/2][MAXN/2];
int _mp[MAXN*2][MAXN/2][MAXN/2];

int Q(int fa,int u,int dep){
    if(dep == 0)return 1;
    assert(fa != u); 
    if(chk(fa,u))return f[u][dep];
    else return g[u][dep] - f[up[fa][u]][dep-1];
}

namespace _{
    int dep[MAXN],fa[MAXN];
    void dfs(int u){
        dfn[u] = ++dtot; sz[u] = 1;
        for(auto v : e[u])if(v != fa[u]){
            fa[v] = u,dep[v] = dep[u]+1;
            dfs(v);
            sz[u] += sz[v];
        }
    }
    void rdfs(int u,int r,int dep,int fa){
        if(u<=rn){
            g[r][dep]++;
            if(chk(r,u))f[r][dep]++;
        }
        for(auto v : e[u])if(v != fa)rdfs(v,r,dep+1,u);
    }
    void pre(){
        dfs(1);
        int u = 1;for(int i=2;i<=n;i++)if(dep[u] < dep[i])u = i;
        dep[u] = fa[u] = 0;dtot = 0; dfs(u); 
        u = 1; for(int i=2;i<=n;i++)if(dep[u] < dep[i])u = i;
        assert(dep[u] % 2 == 0); 
        len = dep[u]/2;
        r = u; for(int i=1;i<=len;i++)r = fa[r];

        dep[1] = fa[1] = 0;dtot = 0;dfs(1);
        //
        for(int i=1;i<=n;i++)rdfs(i,i,0,0);
        for(int i=1;i<=n;i++)for(int j=1;j<=n;j++)if(i!=j && chk(j,i)){
            int& p = up[i][j]; p = i; while(fa[p] != j)p = fa[p];
        }
    }
}

int dp(int x,int len,int fa,int sum){
    if(len == 0)return 1;
    int id = ::id[x][fa];
    if(vis[id][len][sum])return _mp[id][len][sum];
    vis[id][len][sum] = 1;
    int& res = _mp[id][len][sum];

    vec son,pre,suf; int cnt = 0;
    son.push_back(-1);
    for(auto y : e[x])if(y != fa)son.push_back(y),cnt++;
    for(int i=1;i<=cnt;i++){
        int y = son[i];
    }
    pre.resize(cnt+2,0); suf.resize(cnt+2,0);
    for(int i=1;i<=cnt;i++)pre[i] = pre[i-1] + Q(x,son[i],len-1);
    for(int i=cnt;i>=1;i--)suf[i] = suf[i+1] + Q(x,son[i],len-1);
    if(fa){ //往父亲的方向走
        int num = pre[cnt],S = 0;
        for(int c=1;c<=num;c++){
            if(c<num && !sum)continue;
            int rc = num-c;
            int w = C[sum+rc-1][sum-1];
            add(S,1ll*w*dp(fa,len-1,x,c)%mod);
        }
        add(res,1ll*S*fac[num]%mod);
    }   
    //往儿子的方向走
    int rest = fa ? Q(x,fa,len-1) : 0;
    for(int i=1;i<=cnt;i++)if(pre[i] != pre[i-1]){
        int y = son[i];
        int num = pre[i-1] + suf[i+1];
        int w = 1ll*fac[rest]*fac[num]%mod*C[sum+rest+num][sum+rest]%mod;
        add(res,1ll*w*dp(y,len-1,x,sum+num+rest)%mod);
        
    }
    return res;
}

int main(){
    //freopen("tree.in","r",stdin);
    //freopen("tree.out","w",stdout);

    fac[0] = 1; for(int i=1;i<=M;i++)fac[i] = 1ll*fac[i-1]*i%mod;
    for(int i=0;i<=M;i++){
        C[i][0] = 1;
        for(int j=1;j<=i;j++)C[i][j] = addv(C[i-1][j-1],C[i-1][j]);
    }
    //
    cin>>n; rn = n;
    for(int i=1,u,v;i<n;i++){
        cin>>u>>v; int p = i+n;
        link(u,p); link(v,p);
    }
    n += (n-1);
    
    _::pre();

    id[r][0] = ++ic;
    for(int u=1;u<=n;u++)for(auto v : e[u])id[u][v] = ++ic;
    int ans = dp(r,len,0,0);
    cout<<ans<<endl;

    return 0;
}