#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
vector <ll> X, Y;
vector <pll> LX[202020], LY[202020];
vector <pll> PX[202020], PY[202020], Z[202020];
vector <pll> K;
vector <ll> L[202020], P[202020];
set <pll> S;
ll A[202020], B[202020], C[202020], D[202020];
ll T[606060], U[202020];
ll n, v, e, w, h, sz;
ll find(ll p) { return p == U[p]? p : U[p] = find(U[p]); }
void group(ll a, ll b)
{
U[find(a)] = find(b);
}
void insert(ll p, ll v)
{
p += sz;
for(;p;p>>=1) T[p] += v;
}
ll get_sum(ll l, ll r)
{
ll ret = 0;
l += sz, r += sz;
for(;l<r;){
if(l & 1) ret += T[l];
if(~r & 1) ret += T[r];
l = l+1 >> 1;
r = r-1 >> 1;
}
if(l == r) ret += T[l];
return ret;
}
ll intersects(vector <pll> *E, vector <pll> *V, ll x)
{
ll i, ret = 0;
for(i=0;i<=x;i++){
for(auto j: V[i]) insert(j.first, j.second);
for(auto j: E[i]) ret += get_sum(j.first + 1, j.second - 1);
}
return ret;
}
int main()
{
ll i, a, b, c, d;
scanf("%lld%lld%lld", &w, &h, &n);
X.push_back(0); Y.push_back(0);
X.push_back(w); Y.push_back(h);
for(i=1;i<=n;i++){
scanf("%lld%lld%lld%lld", A+i, B+i, C+i, D+i);
X.push_back(A[i]); Y.push_back(B[i]);
X.push_back(C[i]); Y.push_back(D[i]);
}
n ++; A[n] = 0, B[n] = 0, C[n] = w, D[n] = 0;
n ++; A[n] = 0, B[n] = h, C[n] = w, D[n] = h;
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;
sort(X.begin(), X.end());
X.erase(unique(X.begin(), X.end()), X.end());
sort(Y.begin(), Y.end());
Y.erase(unique(Y.begin(), Y.end()), Y.end());
for(sz=1;sz<X.size() && sz<Y.size();sz<<=1);
for(i=1;i<=n;i++){
a = lower_bound(X.begin(), X.end(), A[i]) - X.begin();
b = lower_bound(Y.begin(), Y.end(), B[i]) - Y.begin();
c = lower_bound(X.begin(), X.end(), C[i]) - X.begin();
d = lower_bound(Y.begin(), Y.end(), D[i]) - Y.begin();
if(a == c){
LX[a].push_back(pll(b, d));
PY[b].push_back(pll(a, 1));
PY[d+1].push_back(pll(a, -1));
if(b+1 <= d){
Z[b+1].push_back(pll(a, 1));
Z[d].push_back(pll(a, -1));
}
}
else{
LY[b].push_back(pll(a, c));
PX[a].push_back(pll(b, 1));
PX[c+1].push_back(pll(b, -1));
}
K.push_back(pll(a, b));
K.push_back(pll(c, d));
}
sort(K.begin(), K.end());
K.erase(unique(K.begin(), K.end()), K.end());
v = K.size() + intersects(LY, Z, (ll)Y.size());
e = n + intersects(LX, PX, (ll)X.size()) + intersects(LY, PY, (ll)Y.size());
if(e > 5000000){
printf("%lld\n", e - v + 1);
return 0;
}
for(i=1;i<=n;i++){
A[i] = a = lower_bound(X.begin(), X.end(), A[i]) - X.begin();
B[i] = b = lower_bound(Y.begin(), Y.end(), B[i]) - Y.begin();
C[i] = c = lower_bound(X.begin(), X.end(), C[i]) - X.begin();
D[i] = d = lower_bound(Y.begin(), Y.end(), D[i]) - Y.begin();
U[i] = i;
if(a == c) L[a].push_back(i);
else{
P[a].push_back(i);
P[c+1].push_back(-i);
}
}
for(i=0;i<=X.size();i++){
for(auto j: P[i]){
if(j < 0) S.erase(pll(B[-j], -j));
else S.insert(pll(B[j], j));
}
for(auto j: L[i]){
auto it1 = S.lower_bound(pll(B[j], 0));
auto it2 = S.lower_bound(pll(D[j], 1e9));
for(; it1 != it2; it1++){
group(j, it1 -> second);
}
}
}
c = 0;
for(i=1;i<=n;i++) c += (i == U[i]);
printf("%lld\n", e - v + c );
return 0;
}
