#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp> 
#include <ext/pb_ds/tree_policy.hpp> 
 
#pragma GCC optimize ("O3")
#pragma GCC optimize ("unroll-loops")
#pragma GCC target("avx2,sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
 
using namespace __gnu_pbds; 
using namespace std;
 
#define ld long double
#define pb push_back
#define IOS ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define ll long long
#define int long long
#define ull unsigned long long 
#define pii pair<int,int>
#define vii vector<int>
#define f first
#define s second
// #define endl "\n"
#define all(container) container.begin(), container.end()
#define onlyunique(v) v.erase(unique(all(v)), v.end());
 
#define TRACE
#ifdef AYUSH
#define trace(...) __f(#__VA_ARGS__, __VA_ARGS__)
template <typename Arg1>
void __f(const char* name, Arg1&& arg1){
    cout << name << " : " << arg1 << endl;
}
template <typename Arg1, typename... Args>
void __f(const char* names, Arg1&& arg1, Args&&... args){
    const char* comma = strchr(names + 1, ',');cout.write(names, comma - names) << " : " << arg1<<" | ";__f(comma+1, args...);
}
#else
#define trace(...)
#endif
 
template <typename T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template <class T> ostream& operator << (ostream &os, const vector<T> &v) { for (T i : v) os << i << ' '; return os; }
template <class T> ostream& operator << (ostream &os, const set<T> &v) { for (T i : v) os << i << ' '; return os; }
template <class T> ostream& operator << (ostream &os, const unordered_set<T> &v) { for (T i : v) os << i << ' '; return os; }
template <class T> ostream& operator << (ostream &os, const ordered_set<T> &v) { for (T i : v) os << i << ' '; return os; }
template <class T> ostream& operator << (ostream &os, const multiset<T> &v) { for (T i : v) os << i << ' '; return os; }
template <class T, class S> ostream& operator << (ostream &os, const pair<T, S> &v) { os << '{'<<v.first << ' ' << v.second << '}'; return os; }
template <class T, class S> ostream& operator << (ostream &os, const unordered_map<T, S> &v) { for (auto i : v) os << '(' << i.first << "=>" << i.second << ')' << ' '; return os; }
template <class T, class S> ostream& operator << (ostream &os, const map<T, S> &v) { for (auto i : v) os << '(' << i.first << "=>" << i.second << ')' << ' '; return os; }
//order_of_key (k) : Number of items strictly smaller than k .
//find_by_order(k) : K-th element in a set (counting from zero)
 
int const mod = 1e9+7;
int const inf = 1e18;
 
int power(int x, int y, int mod = 2e18){ int ans = 1;x %= mod;while(y){if(y&1)ans = (x * ans) % mod;x = (x * x) % mod;y >>= 1;}return ans;}
int modinv(int a, int m){return power(a, m-2, m);}
const ld PI = 3.1415926535897932384626433832795;

// unordered_map<int, set<int>, > hor, ver;
vector<set<int>> hor, ver;
map<int, vector< int > > mp;
map<int, vector<set<int>>> mp1;

void solve() {
    int n, m, x; cin >> n >> m >> x;
    hor.assign(n, set<int>());
    ver.assign(m, set<int>());
    for(int i = 0; i < x; ++i) {
    	int u, v; cin >> u >> v;
    	--u; --v;
    	hor[u].insert(v);
    	ver[v].insert(u);
    }
    int MAX1 = 0, MAX2 = 0;
    int max1 = 0, max2 = 0;
    for(int i = 0; i < m; ++i) {
    	int sz = ver[i].size();
    	mp[sz].pb(i);
    	if(mp[sz].size() <= 1) {
	    	if(sz > MAX1) {
	    		MAX2 = MAX1;
	    		MAX1 = sz;
	    	}
	    	else if(sz > MAX2 || sz == MAX1) {
	    		MAX2 = sz;
	    	}
	    }
    }
    trace(mp);
    for(auto x: hor) {
    	int sz = (x).size();
    	// if(mp1[sz].size() <= 1) {
	    	mp1[sz].pb(x);
	    	if(sz > max1) {
	    		max2 = max1;
	    		max1 = sz;
	    	}
	    	else if(sz > max2 || sz == max1) {
	    		max2 = sz;
	    	}
	    // }
    }
    trace(max1, max2);
    int ans = 0;
    for(auto i: {max1, max2}) {
    	for(auto y: mp1[i]) {
	    	for(int j : {MAX1, MAX2}) {
	    		int sub = 0;
	    		trace(mp[j], y);
	    		for(auto xx: mp[j]) {
	    			if(y.count(xx)) {
	    				ans = max(ans, i + j - 1);
	    			}
	    			else {
	    				ans = max(ans, i + j);
	    				break;
	    			}
	    		}
	    	}
    	}
    }
    cout << ans << endl;

}
signed main() {
    IOS
    int t = 1, T = 1;
    // cin>>t;
    while (t--) {
        // cout<<"Case #"<<T<<": ";
        solve();
        // ++T;
    }
    return 0;
}

Measured memory_bytes: 114532