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

const int N_MAX = 20005;
int capacitate[N_MAX + 1][N_MAX + 1];
int flux[N_MAX + 1][N_MAX + 1];
int vis[N_MAX + 1], p[N_MAX + 1];

std::vector<int> G[N_MAX + 1];

int n, m, e;
int total_nodes;

int bfs(int s, int d) {
    for(auto i = 0; i <= total_nodes; i++) {
        vis[i] = 0;
        p[i] = 0;
    }
    
    std::queue<int> q;
    q.push(s);
    vis[s] = 1;

    while(!q.empty()) {
        auto nod = q.front();
        q.pop();
        for (auto vecin : G[nod]) {
            if(!vis[vecin] && capacitate[nod][vecin] - flux[nod][vecin] > 0) {
                vis[vecin] = 1;
                p[vecin] = nod;
                q.push(vecin);
            }
        }
    }

    if(!vis[d]) {
        return 0;
    }

    std::vector<int> path;
    auto x = d;
    while(x != 0) {
        path.push_back(x);
        x = p[x];
    }

    std::reverse(path.begin(), path.end());
    int flow = 1e9;

    for (auto i = 0; i < path.size() - 1; i++) {
        auto a = path[i];
        auto b = path[i + 1];
        flow = std::min(flow, capacitate[a][b] - flux[a][b]);
    }

    for (auto i = 0; i < path.size() - 1; i++) {
        int a = path[i];
        int b = path[i + 1];
        flux[a][b] += flow;
        flux[b][a] -= flow;
    }

    return flow;
}

int main() {
    std::ifstream fin("cuplaj.in");
    std::ofstream fout("cuplaj.out");

    fin >> n >> m >> e;
    
    int source = 0;
    int sink = n + m + 1;
    total_nodes = sink;
    
    for(auto i = 1; i <= n; i++) {
        capacitate[source][i] = 1;
        G[source].push_back(i);
        G[i].push_back(source);
    }
    
    for(auto i = 0; i < e; i++) {
        int u, v;
        fin >> u >> v;
        auto r_node = n + v;
        capacitate[u][r_node] = 1;
        G[u].push_back(r_node);
        G[r_node].push_back(u);
    }
    
    for(auto i = 1; i <= m; i++) {
        auto r_node = n + i;
        capacitate[r_node][sink] = 1;
        G[r_node].push_back(sink);
        G[sink].push_back(r_node);
    }
    
    auto maxflow = 0;
    while (true) {
        auto flow = bfs(source, sink);
        if(flow == 0) {
            break;
        }
        maxflow += flow;
    }
    
    fout << maxflow << '\n';
    
    for(auto u = 1; u <= n; u++) {
        for(auto v = 1; v <= m; v++) {
            auto r_node = n + v;
            if(flux[u][r_node] == 1) {
                fout << u << ' ' << v << '\n';
            }
        }
    }
    
    fin.close();
    fout.close();
    
    return 0;
}