//#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; typedef signed long long ll; #define pp(...) (void)printf(__VA_ARGS__) #define For(x,to) for(x=0;x<(to);x++) #define ForAuto(x,arr) for(auto& x:arr) #define ForBeginEnd(x,c) for(__typeof(c.begin()) x=c.begin();x!=c.end();x++) #define All(a) (a.begin()),(a.end()) #define Zeros(a) memset(a,0,sizeof(a)) #define Minus(a) memset(a,0xff,sizeof(a)) #define PI 3.14159265 #define EPS (1e-10) #define EPS_eq(a,b) (abs((a)-(b)) < EPS) #pragma GCC diagnostic ignored "-Wconversion" //#define int long long #define INF 1000*1000 int dxy[] = {0, 1, 0, -1, 0}; typedef pair P; void pp_int(int x){ printf("%d\n", x); }; int i,j,k; ll M = 100000009; //ios::sync_with_stdio(false); //------------------------------------------------- set sets, setk; signed main() { ll W,H,N; cin>>W>>H>>N; for(int i=0;i>S>>K; sets.insert(S); setk.insert(K); } ll res = -N; res += H * sets.size(); res += W * setk.size(); res -= setk.size() * sets.size(); cout<