#include<bits/stdc++.h>
using namespace std;
typedef pair< int, int > Point;
enum : int { CREATEY, APPEARX, DELETEY};
  
struct Event {
  int y, idx, type;
  bool operator<(const Event& e) const {
    if(y == e.y) return(type < e.type);
    return(y < e.y);
  }
};
  
struct BinaryIndexedTree
{
  vector< int > data;
  BinaryIndexedTree(int sz)
  {
    data.assign(sz + 2, 0);
  }
  int query(int k)
  {
    int ret = 0;
    for(++k; k > 0; k -= k & -k) ret += data[k];
    return(ret);
  }
  void update(int k, int x)
  {
    for(++k; k < data.size(); k += k & -k) data[k] += x;
  }
};
 
struct SegmentTree
{
  vector< int > isnew;
  int sz;
  SegmentTree(int n)
  {
    sz = 1;
    while(sz < n) sz <<= 1;
    isnew.assign(2 * sz - 1, false);
  }
  inline void AddF(const int a, const int b, int k, int l, int r)
  {
    if(a >= r || b <= l) {
      return;
    } else if(a <= l && r <= b) {
      isnew[k] = true;
    } else {
      AddF(a, b, 2 * k + 1, l, (l + r) >> 1);
      AddF(a, b, 2 * k + 2, (l + r) >> 1, r);
    }
  }
  inline void DelF(const int a, const int b, int k, int l, int r)
  {
    if(a >= r || b <= l) {
      return;
    } else if(a <= l && r <= a + 1) {
      isnew[k] = false;
    } else {
      if(isnew[k]) {
        isnew[2 * k + 1] = true;
        isnew[2 * k + 2] = true;
        isnew[k] = false;
      }
      DelF(a, b, 2 * k + 1, l, (l + r) >> 1);
      DelF(a, b, 2 * k + 2, (l + r) >> 1, r);
    }
  }
  inline void AddF(int a, int b)
  {
    AddF(a, b, 0, 0, sz);
  }
  inline void DelF(const int x)
  {
    DelF(x, x + 1, 0, 0, sz);
  }
  inline bool CheckF(int k)
  {
    k += sz - 1;
    if(isnew[k]) return(true);
    while(k > 0) {
      k = (k - 1) >> 1;
      if(isnew[k]) return(true); 
   } while(k > 0);
    return(false);
  }
};
  
struct UnionFind {
  vector< int > data;
  UnionFind(){};
  inline int Make()
  {
    data.push_back(-1);
    return(data.size() - 1);
  }
  inline bool Unite(int a, int b)
  {
    a = Find(a), b = Find(b);
    if(a == b) return(false);
    if(data[a] > data[b]) swap(a, b);
    data[a] += data[b];
    data[b] = a;
    return(true);
  }
  inline int Find(int k)
  {
    if(data[k] < 0) return(k);
    else return(data[k] = Find(data[k]));
  }
};
  
SegmentTree *tree;
UnionFind *uf;
BinaryIndexedTree *bit;
int decode[200020];
  
  
int Evaluate(int x)
{
  if(tree -> CheckF(x)) {
    tree -> DelF(x);
    return(uf -> Make());
  } else {
    return(decode[x]);
  }
}
  
int Press(int *A, int sz1, int *B, int sz2)
{
  vector< int > nums;
  copy(A, A + sz1, back_inserter(nums));
  copy(B, B + sz2, back_inserter(nums));
  nums.push_back(-1);
  sort(nums.begin(), nums.end());
  nums.erase(unique(nums.begin(), nums.end()), nums.end());
  transform(A, A + sz1, A, [&](int x) {
      return(lower_bound(nums.begin(), nums.end(), x) - nums.begin());
  });
  transform(B, B + sz2, B, [&](int x) {
      return(lower_bound(nums.begin(), nums.end(), x) - nums.begin());
  });
  return(nums.size());
}
  
int main()
{
  int W, H, N;
  int A[100004], B[100004], C[100004], D[100004];
   
  scanf("%d %d %d", &W, &H, &N);
  for(int i = 0; i < N; i++) {
    scanf("%d %d %d %d", &A[i], &B[i], &C[i], &D[i]);
  }
   
  A[N] = 0; B[N] = 0; C[N] = W; D[N] = 0; ++N;
  A[N] = 0; B[N] = 0; C[N] = 0; D[N] = H; ++N;
  A[N] = W; B[N] = 0; C[N] = W; D[N] = H; ++N;
  A[N] = 0; B[N] = H; C[N] = W; D[N] = H; ++N;
  
  W = Press(A, N, C, N);
  
  vector< Event > Events;
  /*
    type = CREATEY: Y?????????????????????
    type = DELETEY: Y????????????????¶????
    type = APPEARX: X????????????
  */
  for(int i = 0; i < N; i++) {
    if(A[i] == C[i]) {
      Events.push_back((Event){B[i], i, CREATEY});
      Events.push_back((Event){D[i], i, DELETEY});
    } else {
      Events.push_back((Event){B[i], i, APPEARX});
    }
  }
  sort(Events.begin(), Events.end());
  
  set< int > pool;
  uf = new UnionFind();
  tree = new SegmentTree(W);
  bit = new BinaryIndexedTree(W);
  pool.insert(0); decode[0] = uf -> Make();
  long long int sz = 0;
  
  for(int i = 0; i < Events.size(); i++) {
    const Event& e = Events[i];
    const int&   x = A[e.idx]; 
    if(e.type == CREATEY) {
      int L = *--pool.lower_bound(x);
      decode[x] = Evaluate(x);
      decode[L] = Evaluate(L);
      decode[x] = decode[L];
      pool.insert(x);
      bit -> update(x, 1);
    } else if(e.type == DELETEY) {
      int L = *--pool.lower_bound(x);
      decode[x] = Evaluate(x);
      decode[L] = Evaluate(L);
      if(uf -> Unite(decode[x], decode[L])) --sz;
      pool.erase(x);
      bit -> update(x, -1);
    } else {
      int x2 = C[e.idx];
      int RSQ = bit -> query(x2) - bit -> query(x - 1) - 1;
      if(RSQ > 0) {
        sz += RSQ;
        tree -> AddF(x, *--pool.upper_bound(x2));
      }
    }
  }
  printf("%lld\n", sz);
}

Measured memory_bytes: 13664