#include <fstream>
#include <iostream>
#include <vector>
#include <cstring>

#define MAXN 10101
#define NOT_EXPLORED 0x3f3f3f3f

#ifndef TRUE
	#define TRUE 1
#endif
#ifndef FALSE
	#define FALSE 0
#endif

using namespace std;

typedef unsigned int uint32;
typedef vector<uint32> Graph;

Graph graph[MAXN];
uint32 usedEdges[MAXN];
uint32 partLeft[MAXN];
uint32 partRight[MAXN];

int MaximumMatching
(
	const Graph graph[],
	const uint32 node
)
{
	if (usedEdges[node])
		return FALSE;
	
	usedEdges[node] = 1;
	
	for (Graph::const_iterator it=graph[node].begin(); it!=graph[node].end(); ++it)
	{
		if (partRight[*it] == NOT_EXPLORED)
		{
			partLeft[node] = *it;
			partRight[*it] = node;
			return TRUE;
		}
	}
	
	for (Graph::const_iterator it=graph[node].begin(); it!=graph[node].end(); ++it)
	{
		if (MaximumMatching(graph, partRight[*it]))
		{
			partLeft[node] = *it;
			partRight[*it] = node;
			return TRUE;
		}
	}
	
	return FALSE;
}

int main()
{
	int n,m,e;
	fstream fin("cuplaj.in", fstream::in);
	fstream fout("cuplaj.out", fstream::out);
	
	fin >> n >> m >> e;
	//cout << n << " " << m << " " << e << endl;
	
	for (int i=0; i<e; ++i)
	{
		int x,y;
		fin >> x >> y;
		//cout << x-1 << " " << y-1 << endl;

		graph[x-1].push_back(y-1);
	}
	
	//cout << "\n";
	
	memset(partLeft, 0x3f, MAXN*sizeof(uint32));
	memset(partRight, 0x3f, MAXN*sizeof(uint32));
	
	int ord;
	do
	{
		ord = 0;
		memset(usedEdges,0,MAXN*sizeof(uint32));
		for (int i=0; i<n; ++i)
			if (partLeft[i] == NOT_EXPLORED)
				ord |= MaximumMatching(graph, i);
	} while(ord);
	
	int maxM=0;
	for (int i=0; i<n; ++i)
	{
		if (partLeft[i] != NOT_EXPLORED)
			maxM++;
	}
	
	fout << maxM << "\n";
	for (int i=0; i<n; ++i)
		if (partLeft[i] != NOT_EXPLORED)
			fout << i+1 << " " << partLeft[i]+1 << "\n";
	
	fin.close();
	fout.close();
	return 0;
}