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

using namespace std;

const int NMAX = 1e4;

vector <int> edges[NMAX * 2 + 1];
int p[2 * NMAX + 1];
bool viz[NMAX * 2 + 1];

bool repair( int node ) {
	viz[node] = true;
	for ( auto vec : edges[node] ) {
		if ( !p[vec] ) {
			p[node] = vec;
			p[vec] = node;
			return true;
		} else if ( !viz[p[vec]] && repair( p[vec] ) ) {
			p[node] = vec;
			p[vec] = node;
			return true;
		}
	}
	return false;
}
int main() {
	ifstream fin( "cuplaj.in" );
	ofstream fout( "cuplaj.out" );
	int n, m, e;
	fin >> n >> m >> e;
	for ( int i = 1, a, b; i <= e; i ++ ) {
		fin >> a >> b;
		edges[a].push_back( b + n );
		edges[b + n].push_back( a );
	}
	int cuplaj = 0, sepoate = true;
	while ( sepoate ) {
		sepoate = false;
		for ( int i = 1; i <= n; i ++ ) viz[i] = false;
		for ( int i = 1; i <= n; i ++ ) {
			if ( repair( i ) ) {
				sepoate = true;
				cuplaj ++;
			}
		}
	}
	fout << cuplaj << '\n';
	for ( int i = 1; i <= n; i ++ ) {
		if ( p[i] ) fout << i << ' ' << p[i] - n << '\n';
	}
}