#include <iostream>
#include <algorithm>
#include <fstream>
#include <vector>
#include <utility>
#include <queue>

class Flux
{
private:
    int _n;
    std::vector<std::vector<int>> _adiac;
    std::vector<std::vector<int>> _capaci;

public:
    std::vector<std::vector<int>> getCapacity() const { return _capaci; }
    int getMaxFlux()
    {
        int total = 0;
        while (1)
        {
            int fluxTotal = 0;
            std::queue<int> q;
            std::vector<int> generator(_adiac.size(), 0);
            std::vector<bool> mark(_adiac.size(), 0);
            q.push(0);
            mark[0] = true;

            while (!q.empty())
            {
                int nod = q.front();
                q.pop();
                if (nod == this->_n) // aici o sa vedem din toate caile formate daca putem adauga flux ca sa nu refacem bfs-ul iar si iar;
                {

                    for (auto &&contestant : this->_adiac[nod])
                    {
                        if (this->_capaci[contestant][nod] == 0 or mark[contestant] == 0)
                            continue;

                        int fluxx = this->_capaci[contestant][nod];
                        int checkFlux = contestant;
                        while (checkFlux != 0)
                        {
                            fluxx = std::min(fluxx, this->_capaci[generator[checkFlux]][checkFlux]);
                            checkFlux = generator[checkFlux];
                        }

                        fluxTotal += fluxx;
                        this->_capaci[nod][contestant] += fluxx;
                        this->_capaci[contestant][nod] -= fluxx;
                        checkFlux = contestant;
                        while (checkFlux != 0)
                        {
                            this->_capaci[checkFlux][generator[checkFlux]] += fluxx;
                            this->_capaci[generator[checkFlux]][checkFlux] -= fluxx;
                            checkFlux = generator[checkFlux];
                        }
                    }
                    break;
                }

                for (auto &&vecin : this->_adiac[nod])
                {
                    if (this->_capaci[nod][vecin] != 0 and mark[vecin] == 0)
                    {
                        mark[vecin] = 1;
                        generator[vecin] = nod;
                        q.push(vecin);
                    }
                }
            }
            if (fluxTotal == 0)
            {
                break;
            }
            total += fluxTotal;
        }
        return total;
    }
    Flux(const std::vector<std::vector<int>> &, std::vector<std::vector<int>>, const int &);
    ~Flux() = default;
};

Flux::Flux(const std::vector<std::vector<int>> &v, std::vector<std::vector<int>> cap, const int &n) : _n{n}, _adiac{std::move(v)}, _capaci{std::move(cap)} {}
int main()
{
    std::ifstream cin("cuplaj.in");
    std::ofstream cout("cuplaj.out");

    short n, m;
    int x, y, e;
    cin >> n >> m >> e;
    const int magic = n + m + 2;
    std::vector<std::vector<int>> v(magic);
    std::vector<std::vector<int>> capaci(magic, std::vector<int>(magic, 0));

    for (size_t i = 1; i <= n; i++)
    {
        v[0].push_back(i);
        v[i].push_back(0);
        capaci[0][i] = 1;
    }
    for (size_t i = 1; i <= m; i++)
    {

        v[m + n + 1].push_back(n + i);
        v[n + i].push_back(n + m + 1);
        capaci[n + i][m + n + 1] = 1;
    }
    for (size_t j = 0; j < e; j++)
    {
        cin >> x >> y;
        v[x].push_back(y + n);
        v[y + n].push_back(x);
        capaci[x][n + y] = 1;
    }

    Flux asd{v, capaci, n + m + 1};
    cout << asd.getMaxFlux() << '\n';

    capaci = asd.getCapacity();
    for (size_t i = 1; i <= n; i++)
        for (auto &&mergem : v[i])
        {
            if (capaci[i][mergem] == 0 and mergem != 0) // daca capacitatea ramasa e 0 si j nu e nodul de start ->
            {
                cout << i << ' ' << mergem - n << "\n";
            }
        }
}