#pragma GCC optimze(2)
#include<bits/stdc++.h>
#define rep(i, a, b) for(int i = (a); i <= (b); i++)
#define per(i, a, b) for(int i = (a); i >= (b); i--)
#define sz(t) (int)t.size()
#define all(t) t.begin(), t.end()
#define endl '\n'
#define debug(x) cout << #x << ": " << x << endl;
typedef long long ll;
using namespace std;
typedef pair<ll, ll> pll;
const ll N = 4002;
const ll mod = 998244535;

int n;
vector<int>ve[N];
int c[N][N], siz[N], f[N];
ll dp[N][2][N];
ll temp[2][4002];

struct Qmod
{
    ll m, p;
    void init(ll pp) {m = ((__int128)1 << 64) / pp; p = pp;}
    ll operator ()(ll x)
    {
        return x - ((__int128)(x) * m >> 64) * p;
    }
}mo;

void init_com()
{
    rep(i, 0, N - 1) c[i][0] = 1;
    rep(i, 1, N - 1)
    {
        rep(j, 1, i)
        {
            c[i][j] = mo(c[i - 1][j] + c[i - 1][j - 1]);
        }
    }
    f[0] = 1;
    rep(i, 1, N - 1)
    {
        f[i] = mo(f[i - 1] * i);
    }
}

void dfs(ll u, ll fa)
{
    siz[u]++;
    dp[u][1][0] = 1;
    for(auto v : ve[u])
    {
        if(v != fa)
        {
            dfs(v, u);
            rep(i, 0, 1)
            {
                rep(j, 0, siz[u] + siz[v])
                {
                    temp[i][j] = 0;
                }
            }
            rep(i, 0, siz[u] - 1)
            {
                rep(j, 0, siz[v] - 1)
                {
                    rep(k, max(0ll, llabs(i - j) - 2), min(i + j + 2, n - siz[u] - siz[v]))
                    {
                        int x;
                        x = i + j - k;
                        if(x % 2 == 0 && x >= 0)
                        {
                            x /= 2;
                            temp[0][k] += mo(mo(mo(mo(dp[u][0][i] * dp[v][0][j]) * c[i][x]) * c[j][x]) * f[x]);
                            temp[0][k] = mo(temp[0][k]);
                        }
                        x = i + j - k + 1;
                        if(x % 2 == 0 && x >= 0)
                        {
                            x /= 2;
                            temp[0][k] += mo(mo(mo(mo(dp[u][0][i] * dp[v][1][j]) * c[i][x]) * c[j + 1][x]) * f[x]);
                            temp[0][k] = mo(temp[0][k]);
                        }
                        x = i + j - k + 1;
                        if(x % 2 == 0 && x / 2 >= 1)
                        {
                            x /= 2;
                            temp[0][k] += mo(mo(mo(mo(dp[u][1][i] * dp[v][0][j]) * c[i][x - 1]) * c[j][x]) * f[x]);
                            temp[0][k] = mo(temp[0][k]);
                        }
                        x = i + j - k + 2;
                        if(x % 2 == 0 && x / 2 >= 1)
                        {
                            x /= 2;
                            temp[0][k] += mo(mo(mo(mo(dp[u][1][i] * dp[v][1][j]) * c[i][x - 1]) * c[j][x]) * f[x]);
                            temp[0][k] = mo(temp[0][k]);
                            temp[0][k] += mo(mo(mo(mo(mo(dp[u][1][i] * dp[v][1][j]) * c[i][x - 1]) * c[j][x - 1]) * f[x - 1]) * (x - 1));
                            temp[0][k] = mo(temp[0][k]);
                        }
                        x = i + j - k;
                        if(x % 2 == 0 && x >= 0)
                        {
                            x /= 2;
                            temp[1][k] += mo(mo(mo(mo(dp[u][1][i] * dp[v][0][j]) * c[i][x]) * c[j][x]) * f[x]);
                            temp[1][k] = mo(temp[1][k]);
                        }
                        x = i + j + 1 - k;
                        if(x % 2 == 0 && x >= 0)
                        {
                            x /= 2;
                            temp[1][k] += mo(mo(mo(mo(dp[u][1][i] * dp[v][1][j]) * c[i][x]) * c[j][x]) * f[x]);
                            temp[1][k] = mo(temp[1][k]);
                            if(x) temp[1][k] += mo(mo(mo(mo(dp[u][1][i] * dp[v][1][j]) * c[i][x]) * c[j][x - 1]) * f[x]);
                            temp[1][k] = mo(temp[1][k]);
                        }
                    }
                }
            }
            siz[u] += siz[v];
            rep(i, 0, 1)
            {
                rep(j, 0, siz[u])
                {
                    dp[u][i][j] = temp[i][j];
                }
            }
        }
    }
}

void solve()
{
    cin >> n;
    n *= 2;
    rep(i, 2, n)
    {
        ll u, v;
        cin >> u >> v;
        ve[u].push_back(v);
        ve[v].push_back(u);
    }
    dfs(1, 0);
    cout << dp[1][0][0];
}
//562347296
int main()
{
    // freopen("test.in","r",stdin);
    // freopen("test.out","w",stdout);

    ios::sync_with_stdio(0);
    cin.tie(0),cout.tie(0);
    int T=1;
    init_com();
    mo.init(mod);
    // cin>>T;
    while(T--)
    {
        solve();
    }
    return 0;
}