#include<bits/stdc++.h>
#define ll long long
#define ull unsigned long long
#define db double
#define mp make_pair
#define pii pair<int, int>
#define pb push_back
#define mp make_pair
#define FR first
#define SE second
using namespace std;
inline int read() {
  int x = 0; bool op = false;
  char c = getchar();
  while(!isdigit(c))op |= (c == '-'), c = getchar();
  while(isdigit(c))x = (x << 1) + (x << 3) + (c ^ 48), c = getchar();
  return op ? -x : x;
}
const int N = 5e3 + 10;
const int P = 998244353;
void add(int &a, int b) {a += b; a >= P ? a -= P : 0;}
void sub(int &a, int b) {a -= b; a < 0 ? a += P : 0;}
int n, m, k;
int tot1, tot2;
int ls1[N], ls2[N];
pii a[N];
void disc() {
  for(int i = 1; i <= k; i++)ls1[++tot1] = a[i].FR;
  for(int i = 1; i <= k; i++)ls2[++tot2] = a[i].SE;
  sort(ls1 + 1, ls1 + 1 + tot1);
  tot1 = unique(ls1 + 1, ls1 + 1 + tot1) - (ls1 + 1);
  sort(ls2 + 1, ls2 + 1 + tot2);
  tot2 = unique(ls2 + 1, ls2 + 1 + tot2) - (ls2 + 1);
  for(int i = 1; i <= k; i++) {
    a[i].FR = lower_bound(ls1 + 1, ls1 + 1 + tot1, a[i].FR) - ls1;
    a[i].SE = lower_bound(ls2 + 1, ls2 + 1 + tot2, a[i].SE) - ls2;
  }
  return ;
}
vector<int> A[N];
int sum1[N][N], sum2[N][N], vis[N][N];
int calc2(int l, int r) {
  int i6 = 166374059, res = 0;
  auto _calc = [&](int r) {
    int v1 = 1ll * r * (r + 1) % P, v2 = (2ll * r + 1) % P;
    return 1ll * v1 * v2 % P * i6 % P;
  };
  add(res, _calc(r)); sub(res, _calc(l - 1));
  return res;
}
int calc3(int l, int r) {
  int i2 = 499122177, res = 0;
  auto _calc = [&](int r) {
    int v = 1ll * r * (r + 1) % P * i2 % P;
    return 1ll * v * v % P;
  };
  add(res, _calc(r)); sub(res, _calc(l - 1));
  return res;
}
int calc4(int l, int r) {
  int i30 = 432572553, res = 0;
  auto _calc = [&](int r) {
    int v1 = 1ll * r * (r + 1) % P;
    int v2 = (2ll * r + 1) % P;
    int v3 = (3ll * r % P * r % P + 3ll * r % P - 1) % P;
    return 1ll * v1 * v2 % P * v3 % P * i30 % P;
  };
  add(res, _calc(r)); sub(res, _calc(l - 1));
  return res;
}
int Calc(int tv1, int td1, int tv2, int td2, int l, int r) {
  int res = 0;
  add(res, 1ll * tv1 * tv2 % P * calc2(l, r) % P);
  add(res, 1ll * (1ll * tv1 * td2 % P + 1ll * tv2 * td1 % P) % P * calc3(l, r) % P);
  add(res, 1ll * td1 * td2 % P * calc4(l, r) % P);
  return res;
}
int calc(int x, int y, int z, int w) {
  int res = 0;
  x = ls1[x]; y = ls1[y]; z = ls2[z]; w = ls2[w];
  int st = max(y - x + 2, w - z + 2);
  vector<int> p = {st, y + 1, n - x + 1, w + 1, m - z + 1, min(n, m) + 1};
  sort(p.begin(), p.end());
  p.erase(unique(p.begin(), p.end()), p.end());
  for(int i = 0; i < p.size(); i++) {
    if(p[i] < st)continue;
    if(p[i] > min(n, m))continue;
    int tv1 = 1, td1 = 0, tv2 = 1, td2 = 0;
    int l = p[i], r = p[i + 1] - 1;
    if(l > r)continue;
    (x - 1 < n - p[i] ? add(tv1, x - 1) : (add(tv1, n), sub(td1, 1)));
    (y - p[i] + 1 > 0 ? (sub(tv1, (y + 1) % P), add(td1, 1)) : void());
    (z - 1 < m - p[i] ? add(tv2, z - 1) : (add(tv2, m), sub(td2, 1)));
    (w - p[i] + 1 > 0 ? (sub(tv2, (w + 1) % P), add(td2, 1)) : void());
    add(res, Calc(tv1, td1, tv2, td2, l, r));
  }
  return res;
}
int px[N], py[N], posy[N];
int main() {
  n = read(); m = read(); k = read();
  for(int i = 1; i <= k; i++)a[i].FR = read(), a[i].SE = read();
  disc();
  for(int i = 1; i <= k; i++) {
    vis[a[i].FR][a[i].SE] = 1;
    sum1[a[i].FR][a[i].SE] = 1;
    sum2[a[i].FR][a[i].SE] = 1;
  }
  int ans = Calc(n + 1, P - 1, m + 1, P - 1, 1, min(n, m));
  sort(a + 1, a + 1 + k);
  iota(px + 1, px + 1 + k, 1);
  sort(px + 1, px + 1 + k, [&](int x, int y) {return a[x].FR < a[y].FR;});
  iota(py + 1, py + 1 + k, 1);
  sort(py + 1, py + 1 + k, [&](int x, int y) {return a[x].SE < a[y].SE;});
  for(int i = 1; i <= k; i++)sub(ans, calc(a[i].FR, a[i].FR, a[i].SE, a[i].SE));
  for(int i = 1; i <= k; i++)posy[py[i]] = i;
  for(int i = 1; i <= k; i++) {
    vector<int> vis(k + 1), L(k + 1), R(k + 1);
    for(int j = i; j <= k; j++)vis[posy[px[j]]] = true;
    for(int j = 1; j <= k; j++)L[j] = j - 1, R[j] = j + 1;
    auto del = [&](int x) {
      int tl = L[x], tr = R[x];
      if(tl)R[tl] = tr;
      if(tr <= k)L[tr] = tl;
      return ;
    };
    for(int j = 1; j <= k; j++)if(!vis[j])del(j);
    for(int j = k; j >= i; j--) {
      int nl = min(posy[px[i]], posy[px[j]]), nr = max(posy[px[i]], posy[px[j]]);
      if(R[nl] == nr) {
        add(ans, calc(a[px[i]].FR, a[px[j]].FR, a[py[nl]].SE, a[py[nr]].SE));
        if(L[nl])sub(ans, calc(a[px[i]].FR, a[px[j]].FR, a[py[L[nl]]].SE, a[py[nr]].SE));
        if(R[nr] <= k)sub(ans, calc(a[px[i]].FR, a[px[j]].FR, a[py[nl]].SE, a[py[R[nr]]].SE));
        if(L[nl] && R[nr] <= k)add(ans, calc(a[px[i]].FR, a[px[j]].FR, a[py[L[nl]]].SE, a[py[R[nr]]].SE));
      }
      del(posy[px[j]]);
    }
  }
  printf("%d\n", ans);
  return 0;
}