#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MN = 100010;
int V, E, src, snk;
vector<int> la, nxt, oppo, capa;
void init() {
E = 0;
la.clear(); nxt.clear(); oppo.clear(); capa.clear();
la = vector<int>(V, -1);
}
void add(int u, int v, int c) {
nxt.push_back(la[u]);
la[u] = E++;
oppo.push_back(v);
capa.push_back(c);
}
vector<int> dist;
queue<int> q;
bool bfs() {
dist = vector<int>(V, -1);
q.push(src);
dist[src] = 0;
while(!q.empty()) {
int u = q.front(); q.pop();
for(int i = la[u]; i != -1; i = nxt[i]) {
int v = oppo[i];
if(capa[i] && dist[v] == -1) {
dist[v] = dist[u] + 1;
q.push(v);
}
}
}
return dist[snk] != -1;
}
vector<int> laa;
int dfs(int u, int f) {
if(u == snk) return f;
for(int i = laa[u]; i != -1; i = nxt[i]) {
laa[u] = i;
int v = oppo[i];
if(capa[i] && dist[v] == dist[u] + 1) {
if(int tmp = dfs(v, min(f, capa[i]))) {
capa[i] -= tmp;
capa[i ^ 1] += tmp;
return tmp;
}
}
}
return 0;
}
int dinic() {
int tf = 0;
while(bfs()) {
laa = la;
while(int tmp = dfs(src, 1e9)) tf += tmp;
}
return tf;
}
int N, M, K;
vector<int> adj[MN];
unordered_map<int, int> chk[MN];
int who[MN];
void con(int l, int r) {
V = N + M + 2, src = V - 2, snk = V - 1;
init();
for(int i = l; i <= r; i++) {
add(src, i, 1);
add(i, src, 0);
}
for(int i = 0; i < M; i++) {
add(N + i, snk, 1);
add(snk, N + i, 0);
}
for(int u = l; u <= r; u++) {
for(int i = 0; i < adj[u].size(); i++) {
int v = adj[u][i];
add(u, v, 1);
add(v, u, 0);
}
}
}
int main() {
scanf("%d %d %d", &N, &M, &K);
for(int i = 0; i < K; i++) {
int a, b; scanf("%d %d", &a, &b);
a--; b--;
adj[a].push_back(N + b);
adj[N + b].push_back(a);
chk[a][N + b] = 1;
chk[N + b][a] = 1;
}
for(int i = 0; i < M; i++) {
sort(adj[N + i].begin(), adj[N + i].end());
reverse(adj[N + i].begin(), adj[N + i].end());
}
int s = 0, e = N - 1, p = -1, q = -1;
while(s <= e) {
int m = (s + e)>>1;
con(0, m);
if(dinic() == M) {
p = m;
e = m - 1;
}
else s = m + 1;
}
if(p == -1) {
printf("0");
return 0;
}
con(0, p);
dinic();
s = 0, e = p;
while(s <= e) {
int m = (s + e)>>1;
con(m, p);
if(dinic() == M) {
q = m;
s = m + 1;
}
else e = m - 1;
}
con(q, p);
dinic();
memset(who, -1, sizeof(who));
for(int u = q; u <= p; u++) {
for(int i = la[u]; i != -1; i = nxt[i]) {
int v = oppo[i];
if(v != src && !capa[i]) {
who[u] = v;
who[v] = u;
break;
}
}
}
ll ans = N - p;
for(int i = 1; i < N; i++) {
if(who[i - 1] != -1) {
int u = who[i - 1];
bool found = false;
while(p + 1 < N) {
++p;
bool ok = false;
int mn = 1e9, mnp = -1;
for(int j = 0; j < adj[p].size(); j++) {
int v = adj[p][j];
if(v == u) {
who[u] = p;
who[p] = u;
ok = true;
break;
}
int x = who[v];
if(chk[x][u]) {
who[u] = x;
who[x] = u;
who[v] = p;
who[p] = v;
ok = true;
break;
}
if(mn > x) {
mn = x;
mnp = v;
}
}
if(ok) {
found = true;
break;
}
if(mnp != -1) {
who[mn] = -1;
who[mnp] = p;
who[p] = mnp;
}
}
if(!found) break;
}
ans += N - p;
}
printf("%lld", ans);
}
