#include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <unordered_map>
#include <functional>
#include <cstring>
#include <cmath>
#include <ctime>
#include <cstdlib>
using namespace std;
typedef long long llong;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<llong, llong> pll;
int w, h, n, mx;
vector<int> compx, compy;
struct line {
int x1, x2, y, i;
bool operator<(const line &p) const {
return y < p.y;
}
int count(const vector<int> &cx, const vector<int> &cy) {
x1 = lower_bound(cx.begin(), cx.end(), x1) - cx.begin() + 1;
x2 = lower_bound(cx.begin(), cx.end(), x2) - cx.begin() + 1;
y = lower_bound(cy.begin(), cy.end(), y) - cy.begin() + 1;
return x2 - x1;
}
};
struct event {
int x1, x2, y, t, i;
bool operator<(const event &p) const {
if (y != p.y) return y < p.y;
if (t != p.t) return t < p.t;
return x1 < p.x1;
}
};
struct tree {
int sum[1 << 19];
void update(int i, int s, int e, int x, int v) {
if (s == e) {
sum[i] += v;
return;
}
int m = (s + e) / 2;
if (x <= m) update(i << 1, s, m, x, v);
else update(i << 1 | 1, m + 1, e, x, v);
sum[i] = sum[i << 1] + sum[i << 1 | 1];
}
int query(int i, int s, int e, int x, int y) {
if (e < x || y < s) return 0;
if (x <= s && e <= y) return sum[i];
int m = (s + e) / 2;
return query(i << 1, s, m, x, y) + query(i << 1 | 1, m + 1, e, x, y);
}
int uf[100005];
int seg[1 << 19];
int find(int x) {
if (uf[x]) return uf[x] = find(uf[x]);
return x;
}
int merge(int x, int y) {
if (x && y) {
x = find(x);
y = find(y);
if (x == y) return 0;
uf[x] = y;
return 1;
}
return 0;
}
void lazy(int i) {
if (seg[i]) {
merge(seg[i], seg[i << 1]);
merge(seg[i], seg[i << 1 | 1]);
if (sum[i << 1]) seg[i << 1] = seg[i];
if (sum[i << 1 | 1]) seg[i << 1 | 1] = seg[i];
seg[i] = 0;
}
}
void update1(int i, int s, int e, int x, int v) {
if (s == e) {
seg[i] = v;
return;
}
lazy(i);
int m = (s + e) / 2;
if (x <= m) update1(i << 1, s, m, x, v);
else update1(i << 1 | 1, m + 1, e, x, v);
}
void update2(int i, int s, int e, int x, int y, int v) {
if (sum[i] == 0) return;
if (e < x || y < s) return;
if (x <= s && e <= y) {
merge(seg[i], v);
seg[i] = v;
return;
}
lazy(i);
int m = (s + e) / 2;
update2(i << 1, s, m, x, y, v);
update2(i << 1 | 1, m + 1, e, x, y, v);
}
} seg;
int main() {
scanf("%d%d%d", &w, &h, &n);
vector<line> lx, ly;
for (int i = 0; i < n; ++i) {
int a, b, c, d;
scanf("%d%d%d%d", &a, &b, &c, &d);
if (b == d) lx.push_back({ a, c, b, i + 1 });
else ly.push_back({ b, d, a, i + 1 });
compx.push_back(a);
compx.push_back(c);
compy.push_back(b);
compy.push_back(d);
}
lx.push_back({ 0, w, 0, n + 1 });
lx.push_back({ 0, w, h, n + 2 });
ly.push_back({ 0, h, 0, n + 3 });
ly.push_back({ 0, h, w, n + 4 });
compx.push_back(0);
compx.push_back(w);
compy.push_back(0);
compy.push_back(h);
sort(compx.begin(), compx.end());
compx.erase(unique(compx.begin(), compx.end()), compx.end());
sort(compy.begin(), compy.end());
compy.erase(unique(compy.begin(), compy.end()), compy.end());
mx = compx.size();
llong v = 0;
llong e = 0;
vector<event> ev;
for (line &i : lx) {
int r = i.count(compx, compy);
v += r + 1;
e += r;
ev.push_back({ i.x1, i.x2, i.y, 1, i.i });
}
for (line &i : ly) {
int r = i.count(compy, compx);
v += r + 1;
e += r;
ev.push_back({ i.y, 0, i.x1, 0, i.i });
ev.push_back({ i.y, 0, i.x2, 2, i.i });
}
sort(ev.begin(), ev.end());
for (event e : ev) {
if (e.t == 0) {
seg.update1(1, 1, mx, e.x1, e.i);
seg.update(1, 1, mx, e.x1, 1);
}
else if (e.t == 1) {
seg.update2(1, 1, mx, e.x1, e.x2, e.i);
v -= seg.query(1, 1, mx, e.x1, e.x2);
}
else {
seg.update1(1, 1, mx, e.x1, 0);
seg.update(1, 1, mx, e.x1, -1);
}
}
llong cp = 0;
for (int i = 1; i <= n + 4; ++i) {
if (seg.find(i) == i) ++cp;
}
printf("%lld\n", e - v + cp);
return 0;
}
