#include <bits/stdc++.h>
using namespace std;
const int N = 3609, mod = 998244353, M = 2400;
long long p, fac[N], ifac[N], dp[2][N];
long long pow(long long x, long long y, long long mod) {
  if (y == 0) return 1;
  long long p = pow(x, y / 2, mod);
  return ((p * p % mod) * (1 + (y % 2) * (x - 1))) % mod;
}
void make_fac() {
  fac[0] = 1;
  for (long long i = 1; i < N; i++) fac[i] = fac[i - 1] * i % mod;
  ifac[N - 1] = pow(fac[N - 1], mod - 2, mod);
  for (long long i = N - 2; i >= 0; i--)
    ifac[i] = 1ll * ifac[i + 1] * (i + 1ll) % mod;
}
long long C(int k, int n) {
  if (k > n) return 0;
  return fac[n] * ifac[n - k] % mod * ifac[k] % mod;
}
long long h, w, n, a, b, c, d, t0, t1, ans, row[N], col[N];
vector<long long> v[2];
void make1() {
  long long t = 0;
  row[h] = 1;
  for (long long i = 0; i < h + 1; i++) {
    if (row[i] == 0)
      t++, t0++;
    else {
      if (t > 1) v[0].push_back(t - 1);
      t = 0;
    }
  }
}
void make2() {
  long long t = 0;
  col[w] = 1;
  for (long long i = 0; i < w + 1; i++) {
    if (col[i] == 0)
      t++, t1++;
    else {
      if (t > 1) v[1].push_back(t - 1);
      t = 0;
    }
  }
}
long long e(long long x, long long y) { return C(x, y - x + 1); }
void solve(int src) {
  dp[src][0] = 1;
  for (long long i = 0; i < v[src].size(); i++) {
    for (long long j = M - 1; j >= 1; j--) {
      for (long long k = 1; k < min(v[src][i] / 2 + 2, j + 1); k++)
        dp[src][j] = (dp[src][j] + dp[src][j - k] * e(k, v[src][i])) % mod;
    }
  }
}
int main() {
  make_fac();
  cin >> h >> w >> n;
  for (long long i = 0; i < n; i++) {
    cin >> a >> b >> c >> d;
    a--, b--, c--, d--;
    row[a]++, row[c]++, col[b]++, col[d]++;
    if (a == c)
      row[a--];
    else
      col[b]--;
  }
  make1();
  make2();
  solve(0);
  solve(1);
  for (long long i = 0; i < M; i++) {
    for (long long j = 0; j < M; j++) {
      p = dp[0][i] * dp[1][j] % mod * C(i, t1 - j * 2) % mod *
          C(j, t0 - i * 2) % mod * fac[i] % mod * fac[j] % mod;
      ans = (ans + p) % mod;
    }
  }
  cout << ans;
}
