#include <cstdio>
#include <vector>
#include <algorithm> 
using namespace std; 
const char iname[] = "cuplaj.in";
const char oname[] = "cuplaj.out"; 
#define MAXN  20005
#define FOR(i, a, b)  
for (int i = (int)(a); i <= (int)(b); ++ i) struct list {    int node, cap, flow;    list *nxt, *dup;} ; typedef list* plist; plist adj[MAXN], edge[MAXN];    int n, m, q[MAXN], sel[MAXN], src, sink;  void alloc_edge(plist &nou, plist &dup, int i, int j){    nou = new list, dup = new list;    nou->node = j, dup->node = i;    nou->dup = dup, dup->dup = nou;    nou->nxt = adj[i], dup->nxt = adj[j];    adj[i] = nou, adj[j] = dup;} void read_in(void){    FILE *fi = fopen(iname, "r");    int cnt_edges, x, y;    plist nou, dup;     fscanf(fi, "%d %d %d", &n, &m, &cnt_edges);    for (; cnt_edges --; )    {        fscanf(fi, "%d %d", &x, &y);        alloc_edge(nou, dup, x, y + n);        nou->cap = 1, nou->flow = dup->cap = dup->flow = 0;    }    fclose(fi);     src = 0;    FOR (i, 1, n) {        alloc_edge(nou, dup, src, i);        nou->cap = 1, nou->flow = dup->cap = dup->flow = 0;    }    sink = n+m+1;    FOR (i, n + 1, n + m) {        alloc_edge(nou, dup, i, sink);        nou->cap = 1, nou->flow = dup->cap = dup->flow = 0;    }} int BFS(const int src, const int sink){    int h, t;    plist it;     memset(sel, 0, sizeof(sel));     edge[src] = 0;    for (sel[q[h = t = 0] = src] = 1; h <= t; ++ h)    {        for (it = adj[q[h]]; it; it = it->nxt)            if ((it->cap - it->flow) > 0 && !sel[it->node])            {                sel[q[++ t] = it->node] = 1;                edge[it->node] = it;                if (it->node == sink)                {                    for (it = edge[sink]; it; it = edge[it->dup->node])                        it->flow ++, it->dup->flow --;                    return 1;                }            }    }    return 0;} int main(void){    read_in();    int cuplaj = 0;    while (BFS(src, sink))  cuplaj ++;     FILE *fo = fopen(oname, "w");    fprintf(fo, "%d\n", cuplaj);    FOR (i, 1, n)    {        for (plist it = adj[i]; it; it = it->nxt)            if (it->flow == 1)                fprintf(fo, "%d %d\n", i, it->node - n);    }    fclose(fo);     return 0;}