#include <unordered_map>
#include <algorithm>
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
using namespace std;
ifstream in("cuplaj.in");
ofstream out("cuplaj.out");
const int maxn = 20005;
vector <int> v[maxn];
int dist[maxn];
int tata[maxn];
int sursa, destinatie;

unordered_map <int, int> flux;
unordered_map <int, int> cap;

queue <int> q;
int n;

int make_pair(int x, int y)
{
    return x * maxn + y;
}

bool bfs()
{
    for(int i = 1; i <= n; i++)
        dist[i] = (1 << 30);
    dist[sursa] = 0;
    q.push(sursa);
    while(!q.empty())
    {
        int nod = q.front();
        q.pop();
        if(nod == destinatie)
            continue;
        for(auto it : v[nod])
        {
            if(dist[it] > dist[nod] + 1 && flux[make_pair(nod, it)] < cap[make_pair(nod, it)])
            {
                dist[it] = dist[nod] + 1;
                tata[it] = nod;
                q.push(it);
            }
        }
    }
    if(dist[destinatie] == (1 << 30))
        return 0;
    return 1;
}

vector <pair <int, int> > input;

int main()
{
    int m, e;
    in >> n >> m >> e;
    int ninit = n;
    sursa = n + m + 1;
    destinatie = n + m + 2;
    for(int i = 1; i <= e; i++)
    {
        int x, y;
        in >> x >> y;
        v[x].push_back(y + n);
        v[y + n].push_back(x);
        input.push_back(std::make_pair(x, y));
        cap[make_pair(x, y + n)] = 1;
    }
    for(int i = 1; i <= n; i++)
    {
        v[sursa].push_back(i);
        v[i].push_back(sursa);
        cap[make_pair(sursa, i)] = 1;
    }
    for(int i = 1; i <= m; i++)
    {
        v[i + n].push_back(destinatie);
        v[destinatie].push_back(i + n);
        cap[make_pair(i + n, destinatie)] = 1;
    }
    n = n + m + 2;
    while(bfs())
    {
        for(auto vec : v[destinatie])
        {
            if(dist[vec] == (1 << 30) || flux[make_pair(vec, destinatie)] == cap[make_pair(vec, destinatie)])
                continue;
            tata[destinatie] = vec;
            int act = destinatie;
            vector <int> drum;
            while(tata[act] != 0)
            {
                drum.push_back(act);
                act = tata[act];
            }
            drum.push_back(act);
            reverse(drum.begin(), drum.end());
            int topush = (1 << 30);
            for(int i = 0; i < drum.size() - 1; i++)
                topush = min(topush, cap[make_pair(drum[i], drum[i + 1])] - flux[make_pair(drum[i], drum[i + 1])]);
            for(int i = 0; i < drum.size() - 1; i++)
            {
                flux[make_pair(drum[i], drum[i + 1])] += topush;
                flux[make_pair(drum[i + 1], drum[i])] -= topush;
            }
        }
    }
    int sol = 0;
    for(auto it : v[sursa])
        sol = sol + flux[make_pair(sursa, it)];
    out << sol << "\n";
    for(auto it : input)
        if(flux[make_pair(it.first, it.second + ninit)] == 1)
            out << it.first << " " << it.second << "\n";
    return 0;
}