//Original Code:
//#include <self/utility>
//#include <self/debug>
//using namespace std;
//int n,m;
//map <pii,int> pm;
//int a[300005];
//int b[300005];
//
//int main()
//{
////	freopen("input.txt","r",stdin);
//	cin>>n>>m;
//	int q=0;
//	cin>>q;
//	int x,y;
//	for(int i=0;i<q;i++)
//	{
//		scanf("%d%d",&x,&y);
//		x--;
//		y--;
//		pm[mp(x,y)]=1;
//		a[x]++;
//		b[y]++;
//	}
//	vector <pii> v1,v2;
//	for(int i=0;i<n;i++)
//	{
//		v1.push_back(mp(a[i],i));
//	}
//	for(int i=0;i<m;i++)
//	{
//		v2.push_back(mp(b[i],i));
//	}
//	sort(all(v1));
//	reverse(all(v1));
//	sort(all(v2));
//	reverse(all(v2));
//	while(v1.back().first!=v1[0].first) v1.pop_back();
//	while(v2.back().first!=v2[0].first) v2.pop_back();
//	n=v1.size();
//	m=v2.size();
//	int s=v1[0].first+v2[0].first;
//	for(int i=0;i<n;i++)
//	{
//		for(int j=0;j<m;j++)
//		{
//			if(pm.find(mp(v1[i].second,v2[j].second))==pm.end()) over(s);
//		}
//	}
//	cout<<s-1<<endl;
//	return 0;
//}

//substituted with C++ Inliner
#ifndef _SELF_UTILITY
#define _SELF_UTILITY 1
#include <iostream>
#include <algorithm>
#include <cmath>
#include <stdio.h>
#include <stdlib.h>
#include <vector>
#include <map>
#include <queue>
#include <set>
#include <string>
#include <string.h>
#include <stack>
#include <assert.h>
#include <bitset>
#define Endl endl
#define mp make_pair
#define ll long long 
#define ull unsigned long long
#define pii pair<int,int>
#define over(A) {cout<<A<<endl;exit(0);}
#define all(A) A.begin(),A.end()
#define quickcin ios_base::sync_with_stdio(false);
const int mod=200003;
const int gmod=2;
const int inf=1039074182;
const ll llinf=1LL*inf*inf;
template <typename T1,typename T2> inline void chmin(T1 &x,T2 b) {if(b<x) x=b;}
template <typename T1,typename T2> inline void chmax(T1 &x,T2 b) {if(b>x) x=b;}
template <typename T1,typename T2> inline void chadd(T1 &x,T2 b) {x+=b;if(x>=mod) x-=mod;}
template <typename T1,typename T2> inline void chmul(T1 &x,T2 b) {x=1LL*x*b%mod;}
template <typename T1,typename T2> inline void chmod(T1 &x,T2 b) {x%=b,x+=b;if(x>=b) x-=b;}
#endif

#ifndef _SELF_DEBUG
#define _SELF_DEBUG 1
#ifndef _SELF_OPERATOR
#define _SELF_OPERATOR 1
using namespace std;
template <typename T>
ostream & operator << (ostream& cout,vector<T> vec)
{
	cout<<"{";
	for(int i=0;i<vec.size();i++)
	{
		cout<<vec[i];
		if(i!=(int)vec.size()-1) cout<<',';
	}
	cout<<"}";
	return cout;
}

template <typename T1,typename T2>
ostream & operator << (ostream & cout,pair<T1,T2> p)
{
	cout<<"("<<p.first<<','<<p.second<<")";
	return cout;
}

template <typename T>
ostream & operator << (ostream & cout,set <T> s)
{
	vector <T> t;
	for(auto x:s) t.push_back(x);
	cout<<t;
	return cout;
}

template <typename T>
ostream & operator << (ostream & cout,multiset <T> s)
{
	vector <T> t;
	for(auto x:s) t.push_back(x);
	cout<<t;
	return cout;
}

template <typename T>
ostream & operator << (ostream &cout,queue <T> q)
{
	vector <T> t;
	while(q.size())
	{
		t.push_back(q.front());
		q.pop();
	}
	cout<<t;
	return cout;
}

template <typename T1,typename T2>
ostream & operator << (ostream &cout,map <T1,T2> m)
{
	for(auto &x:m)
	{
		cout<<"Key: "<<x.first<<' '<<"Value: "<<x.second<<endl;
	}
	return cout;
}

template <typename T>
T operator * (vector <T> v1,vector <T> v2)
{
	assert(v1.size()==v2.size());
	int n=v1.size();
	T res=0;
	for(int i=0;i<n;i++)
	{
		res+=v1[i]*v2[i];
	}
	return res;
}

template <typename T1,typename T2>
pair<T1,T2> operator + (pair<T1,T2> x,pair<T1,T2> y)
{
	return make_pair(x.first+y.first,x.second+y.second);
}

template <typename T1,typename T2>
pair<T1,T2> operator - (pair<T1,T2> x)
{
	return make_pair(-x.first,-x.second);
}

template <typename T>
vector<vector<T> > operator ~ (vector<vector <T> > vec)
{
	vector <vector<T> > v;
	int n=vec.size(),m=vec[0].size();
	v.resize(m);
	for(int i=0;i<m;i++)
	{
		v[i].resize(n);
	}
	for(int i=0;i<m;i++)
	{
		for(int j=0;j<n;j++)
		{
			v[i][j]=vec[j][i];
		}
	}
	return v;
}
#endif

void print0x(int x)
{
	std::vector <int> vec;
	while(x)
	{
		vec.push_back(x&1);
		x>>=1;
	}
	std::reverse(vec.begin(),vec.end());
	for(int i=0;i<vec.size();i++)
	{
		std::cout<<vec[i];
	}
	std::cout<<' ';
}

template <typename T>
void print0x(T x,int len)
{
	std::vector <int> vec;
	while(x)
	{
		vec.push_back(x&1);
		x>>=1;
	}
	reverse(vec.begin(),vec.end());
	for(int i=vec.size();i<len;i++)
	{
		putchar('0');
	}
	for(int i=0;i<vec.size();i++)
	{
		std::cout<<vec[i];
	}
	std::cout<<' ';
}
#endif
using namespace std;
int n,m;
map <pii,int> pm;
int a[300005];
int b[300005];

int main()
{
//	freopen("input.txt","r",stdin);
	cin>>n>>m;
	int q=0;
	cin>>q;
	int x,y;
	for(int i=0;i<q;i++)
	{
		scanf("%d%d",&x,&y);
		x--;
		y--;
		pm[mp(x,y)]=1;
		a[x]++;
		b[y]++;
	}
	vector <pii> v1,v2;
	for(int i=0;i<n;i++)
	{
		v1.push_back(mp(a[i],i));
	}
	for(int i=0;i<m;i++)
	{
		v2.push_back(mp(b[i],i));
	}
	sort(all(v1));
	reverse(all(v1));
	sort(all(v2));
	reverse(all(v2));
	while(v1.back().first!=v1[0].first) v1.pop_back();
	while(v2.back().first!=v2[0].first) v2.pop_back();
	n=v1.size();
	m=v2.size();
	int s=v1[0].first+v2[0].first;
	for(int i=0;i<n;i++)
	{
		for(int j=0;j<m;j++)
		{
			if(pm.find(mp(v1[i].second,v2[j].second))==pm.end()) over(s);
		}
	}
	cout<<s-1<<endl;
	return 0;
}


Measured memory_bytes: 32816