#include <bits/stdc++.h>
#define sz(X) (int)((X).size())
#define entire(X) X.begin(),X.end()
using namespace std; typedef long long ll;
void OJize(){cin.tie(NULL);ios_base::sync_with_stdio(false);}
template <class T1, class T2>ostream&operator<<(ostream &os,pair<T1,T2>const&x){os<<'('<<x.first<<", "<<x.second<<')';return os;}
template <class Ch, class Tr, class Container>basic_ostream<Ch,Tr>&operator<<(basic_ostream<Ch,Tr>&os,Container const&x){for(auto&y:x)os<<y<<" ";return os;}
template <typename T>
struct Compress{
int n; vector<T> arr;
void add(T x){arr.push_back(x); n++;}
void init(){sort(entire(arr)),
arr.erase(unique(entire(arr)), arr.end()), n=arr.size();}
int lb(T x){return lower_bound(entire(arr), x) - arr.begin();}
};
struct DisjointSet{
vector<int> par;
DisjointSet(int n): par(n) {iota(entire(par), 0);}
void un(int x, int y){par[fd(x)] = fd(y);} // yr becomes parent
int fd(int x){return par[x]!=x? (par[x]=fd(par[x])):x;}
};
template <typename T>
struct Fenwick{
int n; vector<T> arr;
Fenwick(int N): n{N}, arr(N) {}
void add(int i, T val){
while(i < n) arr[i]+= val, i |= i+1;
}
T getsum(int i){
T res = 0;
while(i >= 0) res+= arr[i], i = (i&(i+1))-1;
return res;
}
T intersum(int i, int j){
if(j < i) return 0;
return i? (getsum(j) - getsum(i-1)) : getsum(j);
}
};
int main(){OJize();
int w,h,n; cin>>w>>h>>n;
vector<tuple<int,int,int,int,int>> ev; // y, type, l, r, idx
Compress<int> C;
C.add(0), C.add(w);
// type 1 = vertical start (uses l=r)
// type 2 = horizontal (uses l, r)
// type 3 = vertical end (uses l=r)
for(int i=0; i<n; i++){
int xa,ya,xb,yb; cin>>xa>>ya>>xb>>yb;
C.add(xa), C.add(xb);
if(xa == xb){
ev.push_back({ya, 1, xa, xb, i});
ev.push_back({yb, 3, xa, xb, i});
}
else ev.push_back({ya, 2, xa, xb, i});
}
ev.push_back({0,2,0,w,n}), ev.push_back({h,2,0,w,n+1});
ev.push_back({0,1,0,0,n+2}), ev.push_back({0,1,w,w,n+3});
ev.push_back({h,3,0,0,n+2}), ev.push_back({h,3,w,w,n+3});
C.init(), sort(entire(ev));
Fenwick<int> F(sz(C.arr));
// count V and E
ll V=0, E=0, COMP=0;
for(auto [y,ty,x1,x2,_]: ev){
x1 = C.lb(x1), x2 = C.lb(x2);
if(ty == 1) F.add(x1, 1), V++;
else if(ty == 2){
ll ic = F.intersum(x1, x2);
V+= ic+2, E+= 2*ic+1;
}
else if(ty == 3) F.add(x1, -1), V++, E++;
}
// count COMP
DisjointSet DS(n+4);
COMP = 1;
map<int,int> vert; vert[w+1] = -1;
for(auto [y,ty,x1,x2,idx]: ev){
x1 = C.lb(x1), x2 = C.lb(x2);
if(V > 2000000) break; // subtask 4
if(ty == 1){
vert[x1] = idx;
}
else if(ty == 2){
auto it = vert.lower_bound(x1);
for(; it->first<=x2; it++)
DS.un(idx, it->second);
}
else if(ty == 3){
vert.erase(x1);
}
}
if(V <= 2000000){
COMP = 0;
for(int i=0; i<sz(DS.par); i++)
COMP+= DS.fd(i) == i;
}
cout << E-V+COMP;
}
