#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;  

}