#include<cstdio>

 #include<cstring>

 #include<cstdlib>

 #include<algorithm>

 #include<iostream>

 using namespace std;

 void setIO(const string& s) {

     freopen((s + ".in").c_str(), "r", stdin);

     freopen((s + ".out").c_str(), "w", stdout);

 }

 template<typename Q> Q read(Q& x) {

     static char c, f;

     for(f = ; c = getchar(), !isdigit(c); ) if(c == '-') f = ;

     for(x = ; isdigit(c); c = getchar()) x = x *  + c - '';

     return f && (x = -x), x;

 }

 template<typename Q> Q read() {

     static Q x; return read(x);

 }

 const int N =  + ;

 struct Node {

     int x, y;

     Node(int x = , int y = ) : x(x), y(y) {}

 }p[N];

 bool cmpx(const Node& lhs, const Node& rhs) {

     return lhs.x < rhs.x;

 }

 bool cmpy(const Node& lhs, const Node& rhs) {

     return lhs.y < rhs.y;

 }

 int L, H, n;

 int calc() {

     int ans = ;

     for(int i = ; i < n; i++) {

         int U = H, D = ;

         for(int j = i + ; j < n; j++) {

             ans = max(ans, (p[j].x - p[i].x) * (U - D));

             if(D <= p[j].y && p[j].y <= U) {

                 if(p[j].y > p[i].y) U = p[j].y;

                 else D = p[j].y;

             }

             if(U == D) break;

         }

     }

     return ans;

 }

 int main() {

 #ifdef DEBUG

     freopen("in.txt", "r", stdin);

     freopen("out.txt", "w", stdout);

 #endif

     read(H), read(L), read(n);

     for(int i = ; i < n; i++) {

         int x = read<int>(), y = read<int>();

         p[i] = Node(x, y);

     }

     p[n++] = Node(, );

     p[n++] = Node(, H);

     p[n++] = Node(L, );

     p[n++] = Node(L, H);

     int ans = ;

     sort(p, p + n, cmpy);

     for(int i = ; i < n; i++) {

         ans = max(ans, (p[i].y - p[i-].y) * L);

     }

     sort(p, p + n, cmpx);

     ans = max(ans, calc());

     for(int i = ; i < n; i++) p[i].x *= -;

     reverse(p, p + n);

     printf("%d\n", max(ans, calc()));

     return ;

 }