//freopen("HCN.INP", "r", stdin);
//freopen("HCN.OUT", "w", stdout);
#include <bits/stdc++.h>
using namespace std;
int main(){
ios_base::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
int n, m, k;
cin >> n >> m >> k;
int a[n+1][m+1];
int ps[n+1][m+1];
for (int i = 0; i <= n; i++){
for (int j = 0; j <= m; j++) {
a[i][j] = 0;
ps[i][j] = 0;
}
}
for (int i = 0; i < k; i++){
int x, y; cin >> x >> y;
a[x][y] = 1;
}
ps[1][1] = a[1][1];
for (int i = 2; i <= n; i++) ps[i][1] = ps[i-1][1] + a[i][1];
for (int i = 2; i <= m; i++) ps[1][i] = ps[1][i-1] + a[1][i];
for (int i = 2; i <= n; i++){
for (int j = 2; j <= m; j++) ps[i][j] = a[i][j] + ps[i-1][j] + ps[i][j-1] - ps[i-1][j-1];
}
vector<pair<int, int>> v;
int maxa = 0;
for (int i = 1; i <= n; i++){
for (int j = 1; j <= m; j++){
if (ps[i][j] == 1){
pair<int, int> p;
p.first = j;
p.second = i;
v.push_back(p);
}
}
}
for (int i = 2; i <= n; i++){
for (int j = 2; j <= m; j++){
int sum = ps[i][j] - ps[i - 1][j] - ps[i][j-1] + ps[i-1][j-1];
if (sum == 1){
pair<int, int> p;
p.first = j - 1;
p.second = i - 1;
v.push_back(p);
}
}
}
for (auto i : v) maxa = max(maxa, i.first * i.second);
cout << maxa;
return 0;
}
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