#include <bits/stdc++.h>
#define rep(a, b, c) for (int a = b; a <= c; a++)
#define ALL(x) (x).begin(), (x).end()
#define IOS cin.tie(0)->sync_with_stdio(false)
#ifdef LOCAL
#include "debug.h"
#else
#define deb(...) 42
#endif
#define OPENSTACK
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pii;
const int MAXN = 2e5 + 5;
const int INF = 0x3f3f3f3f;
namespace flow {
    const int N = 6e4 + 5, M = 9e6 + 5;
    struct edge {
        int next, to, w;
    } e[M << 1];
    int n, s, t;
    int head[N], cnt, cur[N], dis[N];
    void init(int n_, int s_, int t_)
    {
        s = s_, t = t_, n = n_, cnt = 0;
        for (int i = 0; i < n; i++) head[i] = -1;
    }
    void add_edge(int u, int v, int w)
    {
        e[cnt] = edge{ head[u], v, w };
        head[u] = cnt;
        cnt++;
        e[cnt] = edge{ head[v], u, 0 };
        head[v] = cnt;
        cnt++;
    }
    bool bfs()
    {
        for (int i = 0; i < n; i++) cur[i] = head[i], dis[i] = -1;
        queue<int> q;
        dis[s] = 0;
        q.push(s);
        while (!q.empty()) {
            int x = q.front();
            q.pop();
            for (int i = head[x]; ~i; i = e[i].next) {
                if (e[i].w) {
                    int y = e[i].to;
                    if (~dis[y]) continue;
                    dis[y] = dis[x] + 1;
                    q.push(y);
                }
            }
        }
        return ~dis[t];
    }
    int dfs(int x, int flow)
    {
        int ans = 0;
        if (x == t) return flow;
        for (int i = cur[x]; ~i; i = e[i].next, cur[x] = i) {
            int y = e[i].to, newflow = min(e[i].w, flow);
            if (dis[y] != dis[x] + 1 || !e[i].w) continue;
            newflow = dfs(y, newflow);
            e[i].w -= newflow;
            e[i ^ 1].w += newflow;
            flow -= newflow;
            ans += newflow;
            if (!flow) break;
        }
        return ans;
    }
    int dinic()
    {
        int ans = 0;
        while (bfs()) ans += dfs(s, numeric_limits<int>::max());
        return ans;
    }
}  // namespace flow
using flow::add_edge;
using flow::dinic;
using flow::init;

void solve()
{
    int L, R, m;
    cin >> L >> R >> m;
    int s = L + R, t = s + 1;
    init(t + 1, s, t);
    vector<array<int, 3>>ec;
    for (int i = 1; i <= m; i++) {
        int x, y;
        cin >> x >> y;
        ec.push_back({ flow::cnt,x,y });
        add_edge(x, y + L, 1);
    }
    for (int i = 0; i < L; i++)add_edge(s, i, 1);
    for (int i = 0; i < R; i++)add_edge(i + L, t, 1);
    auto fl = dinic();
    cout << fl << "\n";
    for (auto [e, x, y] : ec) {
        if (flow::e[e].w == 0) {
            cout << x << " " << y << "\n";
        }
    }
}
signed main()
{
#ifdef LOCAL
#ifdef OPENSTACK
    int size = 128 << 20; // 64MB
    char* p = (char*) malloc(size) + size;
#if (defined _WIN64) or (defined __unix)
    __asm__("movq %0, %%rsp\n" ::"r"(p));
#else
    __asm__("movl %0, %%esp\n" ::"r"(p));
#endif
#endif
#endif
    IOS;
    int _ = 1;
    while (_--) {
        solve();
    }
#ifdef LOCAL
#ifdef OPENSTACK
    exit(0);
#else
    return 0;
#endif
#endif
}