#include <bits/stdc++.h>
using namespace std;
using ll = long long;
template <class t, class u>
void chmax(t& first, u second) {
  if (first < second) first = second;
}
template <class t, class u>
void chmin(t& first, u second) {
  if (second < first) first = second;
}
template <class t>
using vc = vector<t>;
template <class t>
using vvc = vc<vc<t>>;
using pi = pair<int, int>;
using vi = vc<int>;
template <class t, class u>
ostream& operator<<(ostream& os, const pair<t, u>& p) {
  return os << "{" << p.first << "," << p.second << "}";
}
template <class t>
ostream& operator<<(ostream& os, const vc<t>& v) {
  os << "{";
  for (auto e : v) os << e << ",";
  return os << "}";
}
using uint = unsigned;
using ull = unsigned long long;
template <int i, class T>
void print_tuple(ostream&, const T&) {}
template <int i, class T, class H, class... Args>
void print_tuple(ostream& os, const T& t) {
  if (i) os << ",";
  os << get<i>(t);
  print_tuple<i + 1, T, Args...>(os, t);
}
template <class... Args>
ostream& operator<<(ostream& os, const tuple<Args...>& t) {
  os << "{";
  print_tuple<0, tuple<Args...>, Args...>(os, t);
  return os << "}";
}
void print(ll x, int suc = 1) {
  cout << x;
  if (suc == 1) cout << "\n";
  if (suc == 2) cout << " ";
}
ll read() {
  ll i;
  cin >> i;
  return i;
}
vi readvi(int n, int off = 0) {
  vi v(n);
  for (int i = int(0); i < int(n); i++) v[i] = read() + off;
  return v;
}
template <class T>
void print(const vector<T>& v, int suc = 1) {
  for (int i = int(0); i < int(v.size()); i++)
    print(v[i], i == int(v.size()) - 1 ? suc : 2);
}
string readString() {
  string s;
  cin >> s;
  return s;
}
template <class T>
T sq(const T& t) {
  return t * t;
}
void yes(bool ex = true) {
  cout << "Yes" << endl;
  if (ex) exit(0);
}
void no(bool ex = true) {
  cout << "No" << endl;
  if (ex) exit(0);
}
constexpr ll ten(int n) { return n == 0 ? 1 : ten(n - 1) * 10; }
const ll infLL = LLONG_MAX / 3;
const int inf = INT_MAX / 2 - 100;
int topbit(signed t) { return t == 0 ? -1 : 31 - __builtin_clz(t); }
int topbit(ll t) { return t == 0 ? -1 : 63 - __builtin_clzll(t); }
int botbit(signed first) { return first == 0 ? 32 : __builtin_ctz(first); }
int botbit(ll first) { return first == 0 ? 64 : __builtin_ctzll(first); }
int popcount(signed t) { return __builtin_popcount(t); }
int popcount(ll t) { return __builtin_popcountll(t); }
bool ispow2(int i) { return i && (i & -i) == i; }
int mask(int i) { return (int(1) << i) - 1; }
bool inc(int first, int second, int c) {
  return first <= second && second <= c;
}
template <class t>
void mkuni(vc<t>& v) {
  sort(v.begin(), v.end());
  v.erase(unique(v.begin(), v.end()), v.end());
}
ll rand_int(ll l, ll r) {
  static random_device rd;
  static mt19937_64 gen(rd());
  return uniform_int_distribution<ll>(l, r)(gen);
}
template <class t>
int lwb(const vc<t>& v, const t& first) {
  return lower_bound(v.begin(), v.end(), first) - v.begin();
}
using uint = unsigned;
using ull = unsigned long long;
const uint mod = 998244353;
struct mint {
  uint v;
  mint(ll vv = 0) { s(vv % mod + mod); }
  mint& s(uint vv) {
    v = vv < mod ? vv : vv - mod;
    return *this;
  }
  mint operator-() const { return mint() - *this; }
  mint& operator+=(const mint& rhs) { return s(v + rhs.v); }
  mint& operator-=(const mint& rhs) { return s(v + mod - rhs.v); }
  mint& operator*=(const mint& rhs) {
    v = ull(v) * rhs.v % mod;
    return *this;
  }
  mint& operator/=(const mint& rhs) { return *this *= rhs.inv(); }
  mint operator+(const mint& rhs) const { return mint(*this) += rhs; }
  mint operator-(const mint& rhs) const { return mint(*this) -= rhs; }
  mint operator*(const mint& rhs) const { return mint(*this) *= rhs; }
  mint operator/(const mint& rhs) const { return mint(*this) /= rhs; }
  mint pow(int n) const {
    mint res(1), x(*this);
    while (n) {
      if (n & 1) res *= x;
      x *= x;
      n >>= 1;
    }
    return res;
  }
  mint inv() const { return pow(mod - 2); }
  friend ostream& operator<<(ostream& os, const mint& m) { return os << m.v; }
  bool operator<(const mint& r) const { return v < r.v; }
  bool operator==(const mint& r) const { return v == r.v; }
};
const int vmax = (1 << 21) + 10;
mint fact[vmax], finv[vmax], invs[vmax];
void initfact() {
  fact[0] = 1;
  for (int i = int(1); i < int(vmax); i++) {
    fact[i] = fact[i - 1] * i;
  }
  finv[vmax - 1] = fact[vmax - 1].inv();
  for (int i = vmax - 2; i >= 0; i--) {
    finv[i] = finv[i + 1] * (i + 1);
  }
  for (int i = vmax - 1; i >= 1; i--) {
    invs[i] = finv[i] * fact[i - 1];
  }
}
mint choose(int n, int k) { return fact[n] * finv[n - k] * finv[k]; }
mint binom(int first, int second) {
  return fact[first + second] * finv[first] * finv[second];
}
mint catalan(int n) {
  return binom(n, n) - (n - 1 >= 0 ? binom(n - 1, n + 1) : 0);
}
const int nmax = 4010;
const int K = 40;
vi t[nmax];
mint dp[nmax][K];
vc<mint> buf;
mint work[K][K];
void dfs(int v, int p) {
  for (auto c : t[v])
    if (c != p) dfs(c, v);
  memset(work, 0, sizeof(work));
  work[0][0] = 1;
  for (int us = int(0); us < int(K - 1); us++) {
    for (auto c : t[v])
      if (c != p) {
        for (int i = int(0); i < int(K); i++) {
          for (int j = int(0); j < int(K - i - 1); j++) {
            work[us + 1][i + j + 1] += work[us][i] * dp[c][j];
          }
        }
      }
  }
  buf[0] += 1;
  for (int us = int(0); us < int(K); us++)
    for (int i = int(0); i < int(K); i++) dp[v][i] += work[us][i];
  for (int us = int(1); us < int(K); us++) {
    for (int i = int(1); i < int(K); i++)
      if (work[us][i].v) {
        for (int j = int(2); j < int(min((K - 1) / us, (K - 1) / i) + 1); j++) {
          work[us * j][i * j] -= work[us][i];
        }
        for (int j = int(1); j < int(min((K - 1) / us, (K - 1) / i) + 1); j++) {
          buf[i * j] += work[us][i] * i * 2 * invs[us];
        }
      }
  }
}
signed main() {
  cin.tie(0);
  ios::sync_with_stdio(0);
  cout << fixed << setprecision(20);
  initfact();
  int n[2];
  for (int i = int(0); i < int(2); i++) cin >> n[i];
  int k;
  cin >> k;
  if (k % 2) {
    cout << 0 << endl;
    return 0;
  }
  k /= 2;
  vc<mint> x[2];
  for (int w = int(0); w < int(2); w++) {
    for (int i = int(0); i < int(n[w]); i++) t[i].clear();
    memset(dp, 0, sizeof(dp));
    buf.assign(K, 0);
    for (int _ = int(0); _ < int(n[w] - 1); _++) {
      int first, second;
      cin >> first >> second;
      first--;
      second--;
      t[first].push_back(second);
      t[second].push_back(first);
    }
    dfs(0, -1);
    x[w] = buf;
  }
  void(0);
  void(0);
  mint ans = 0;
  for (int i = int(0); i < int(k + 1); i++) {
    ans += x[0][i] * x[1][k - i] * choose(k * 2, i * 2);
  }
  cout << ans << endl;
}
