#include <bits/stdc++.h>
using namespace std;
using ll = long long;

#define ALL(obj) (obj).begin(),(obj).end()
template<class T> using priority_queue_reverse = priority_queue<T,vector<T>,greater<T>>;

constexpr long long MOD = 1'000'000'000LL + 7;
constexpr long long MOD2 = 998244353;
constexpr long long HIGHINF = (long long)1e18;
constexpr long long LOWINF = (long long)1e15;
constexpr long double PI = 3.1415926535897932384626433L;

template <class T> vector<T> multivector(size_t N,T init){return vector<T>(N,init);}
template <class... T> auto multivector(size_t N,T... t){return vector<decltype(multivector(t...))>(N,multivector(t...));}
template <class T> void corner(bool flg, T hoge) {if (flg) {cout << hoge << endl; exit(0);}}
template <class T, class U>ostream &operator<<(ostream &o, const map<T, U>&obj) {o << "{"; for (auto &x : obj) o << " {" << x.first << " : " << x.second << "}" << ","; o << " }"; return o;}
template <class T>ostream &operator<<(ostream &o, const set<T>&obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr) o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;}
template <class T>ostream &operator<<(ostream &o, const multiset<T>&obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr) o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;}
template <class T>ostream &operator<<(ostream &o, const vector<T>&obj) {o << "{"; for (int i = 0; i < (int)obj.size(); ++i)o << (i > 0 ? ", " : "") << obj[i]; o << "}"; return o;}
template <class T, class U>ostream &operator<<(ostream &o, const pair<T, U>&obj) {o << "{" << obj.first << ", " << obj.second << "}"; return o;}
void print(void) {cout << endl;}
template <class Head> void print(Head&& head) {cout << head;print();}
template <class Head, class... Tail> void print(Head&& head, Tail&&... tail) {cout << head << " ";print(forward<Tail>(tail)...);}
template <class T> void chmax(T& a, const T b){a=max(a,b);}
template <class T> void chmin(T& a, const T b){a=min(a,b);}
vector<string> split(const string &str, const char delemiter) {vector<string> res;stringstream ss(str);string buffer; while( getline(ss, buffer, delemiter) ) res.push_back(buffer); return res;}
int msb(int x) {return x?31-__builtin_clz(x):-1;}
void YN(bool flg) {cout << (flg ? "YES" : "NO") << endl;}
void Yn(bool flg) {cout << (flg ? "Yes" : "No") << endl;}
void yn(bool flg) {cout << (flg ? "yes" : "no") << endl;}

/*
 * @title SegmentTree
 */
template<class Operator> class SegmentTree {
	using TypeNode = typename Operator::TypeNode; 
	size_t length;
	size_t num;
	vector<TypeNode> node;
	vector<pair<size_t,size_t>> range;
public:

	//unitで初期化
	SegmentTree(const size_t num): num(num) {
		for (length = 1; length <= num; length *= 2);
		node.resize(2 * length, Operator::unit_node);
		range.resize(2 * length);
		for (int i = 0; i < length; ++i) range[i+length] = make_pair(i,i+1);
		for (int i = length - 1; i >= 0; --i) range[i] = make_pair(range[(i<<1)+0].first,range[(i<<1)+1].second);
	}

	//vectorで初期化
	SegmentTree(const vector<TypeNode> & vec) : num(vec.size()) {
		for (length = 1; length <= vec.size(); length *= 2);
		node.resize(2 * length, Operator::unit_node);
		for (int i = 0; i < vec.size(); ++i) node[i + length] = vec[i];
		for (int i = length - 1; i >= 0; --i) node[i] = Operator::func_node(node[(i<<1)+0],node[(i<<1)+1]);
		range.resize(2 * length);
		for (int i = 0; i < length; ++i) range[i+length] = make_pair(i,i+1);
		for (int i = length - 1; i >= 0; --i) range[i] = make_pair(range[(i<<1)+0].first,range[(i<<1)+1].second);
	}
 
	//同じinitで初期化
	SegmentTree(const size_t num, const TypeNode init) : num(num) {
		for (length = 1; length <= num; length *= 2);
		node.resize(2 * length, Operator::unit_node);
		range.resize(2 * length);
		for (int i = 0; i < length; ++i) node[i+length] = init;
		for (int i = length - 1; i >= 0; --i) node[i] = Operator::func_node(node[(i<<1)+0],node[(i<<1)+1]);
		for (int i = 0; i < length; ++i) range[i+length] = make_pair(i,i+1);
		for (int i = length - 1; i >= 0; --i) range[i] = make_pair(range[(i<<1)+0].first,range[(i<<1)+1].second);
	}
	
	//[idx,idx+1)
	void update(size_t idx, const TypeNode var) {
		if(idx < 0 || length <= idx) return;
		idx += length;
		node[idx] = Operator::func_merge(node[idx],var);
		while(idx >>= 1) node[idx] = Operator::func_node(node[(idx<<1)+0],node[(idx<<1)+1]);
	}

	//[l,r)
	TypeNode get(int l, int r) {
		if (l < 0 || length <= l || r < 0 || length < r) return Operator::unit_node;
		TypeNode vl = Operator::unit_node, vr = Operator::unit_node;
		for(l += length, r += length; l < r; l >>=1, r >>=1) {
			if(l&1) vl = Operator::func_node(vl,node[l++]);
			if(r&1) vr = Operator::func_node(node[--r],vr);
		}
		return Operator::func_node(vl,vr);
	}

	//return [0,length]
	int prefix_binary_search(TypeNode var) {
		if(!Operator::func_check(node[1],var)) return num;
		TypeNode ret = Operator::unit_node;
		size_t idx = 2;
		for(; idx < 2*length; idx<<=1){
			if(!Operator::func_check(Operator::func_node(ret,node[idx]),var)) {
				ret = Operator::func_node(ret,node[idx]);
				idx++;
			}
		}
		return min((idx>>1) - length,num);
	}

	//range[l,r) return [l,r]
	int binary_search(size_t l, size_t r, TypeNode var) {
		if (l < 0 || length <= l || r < 0 || length < r) return -1;
		TypeNode ret = Operator::unit_node;
		size_t off = l;
		for(size_t idx = l+length; idx < 2*length && off < r; ){
			if(range[idx].second<=r && !Operator::func_check(Operator::func_node(ret,node[idx]),var)) {
				ret = Operator::func_node(ret,node[idx]);
				off = range[idx++].second;
				if(!(idx&1)) idx >>= 1;			
			}
			else{
				idx <<=1;
			}
		}
		return off;
	}

	void print(){
		// cout << "node" << endl;
		// for(int i = 1,j = 1; i < 2*length; ++i) {
		// 	cout << node[i] << " ";
		// 	if(i==((1<<j)-1) && ++j) cout << endl;
		// }
		// cout << "lazy" << endl;
		// for(int i = 1,j = 1; i < 2*length; ++i) {
		// 	cout << lazy[i] << " ";
		// 	if(i==((1<<j)-1) && ++j) cout << endl;
		// }
		cout << "vector" << endl;
		cout << "{ " << get(0,1);
		for(int i = 1; i < length; ++i) cout << ", " << get(i,i+1);
		cout << " }" << endl;
	}
};

//一点更新 区間最小
template<class T> struct NodeMaxPointUpdate {
	using TypeNode = T;
	inline static constexpr TypeNode unit_node = -LOWINF;
	inline static constexpr TypeNode func_node(TypeNode l,TypeNode r){return max(l,r);}
	inline static constexpr TypeNode func_merge(TypeNode l,TypeNode r){return r;}
	inline static constexpr bool func_check(TypeNode nodeVal,TypeNode var){return var == nodeVal;}
};

//一点加算 区間総和
template<class T> struct NodeSumPointAdd {
	using TypeNode = T;
	inline static constexpr TypeNode unit_node = 0;
	inline static constexpr TypeNode func_node(TypeNode l,TypeNode r){return l+r;}
	inline static constexpr TypeNode func_merge(TypeNode l,TypeNode r){return l+r;}
	inline static constexpr bool func_check(TypeNode nodeVal,TypeNode var){return var == nodeVal;}
};

//一次関数
template<class T> struct NodeCompositePointUpdate {
	using TypeNode = T;
	inline static constexpr TypeNode unit_node = make_pair(1,0);
	inline static constexpr TypeNode func_node(TypeNode l,TypeNode r){return {r.first*l.first,r.first*l.second+r.second};}
	inline static constexpr TypeNode func_merge(TypeNode l,TypeNode r){return r;}
	inline static constexpr bool func_check(TypeNode nodeVal,TypeNode var){return var == nodeVal;}
};


int main() {
    cin.tie(0);ios::sync_with_stdio(false);
    ll H,W,N,L=300000; cin >> H >> W >> N;
    vector<ll> y_sum(L+1,0),x_sum(L+1,0);
    vector<vector<ll>> edge(L+1);
    for(int i = 0; i < N; ++i) {
        ll y,x;
        cin >> y >> x;
        y_sum[y]++;
        x_sum[x]++;
        edge[x].push_back(y);
    }
    SegmentTree<NodeMaxPointUpdate<ll>> seg(y_sum);
    ll ans = 0;
    for(ll x = 0; x <= L; ++x) {
        for(ll y:edge[x]) {
            ll sum = x_sum[x] + y_sum[y] - 1;
            chmax(ans,sum);
            seg.update(y,-LOWINF);
        }
        {
            ll sum = x_sum[x] + seg.get(0,L+1);
            chmax(ans,sum);
        }
        for(ll y:edge[x]) {
            seg.update(y,y_sum[y]);
        }
    }
    cout << ans << endl;
    return 0;
}


Measured memory_bytes: 48868