#include <cstdio>
#include <bitset>
#include <vector>
#define Nmax 10005
using namespace std;
int n,m,e;
int st[Nmax],dr[Nmax];
vector <int> graf[Nmax];
bitset <Nmax> viz;

void read()
{
    freopen("cuplaj.in","r",stdin);
    freopen("cuplaj.out","w",stdout);
    scanf("%d %d %d",&n,&m,&e);
    int x,y;
    for(int i = 0 ; i < e ; i++)
    {
        scanf("%d %d",&x,&y);
        graf[x].push_back(y);
    }
}

int cmgb(int nod)
{
    if(viz[nod] == true)
        return false;
    viz[nod] = true;
    for(vector <int> :: iterator  it = graf[nod].begin() ; it != graf[nod].end() ; it++)
        if(!st[*it])
        {
            dr[nod] = *it;
            st[*it] = nod;
            return true;
        }
    for(vector <int> :: iterator  it = graf[nod].begin() ; it != graf[nod].end() ; it++)
        if(cmgb(st[*it]))
        {
            dr[nod] = *it;
            st[*it] = nod;
            return true;
        }
    return false;
}


void Solution()
{
    bool done = false;
    int answer= 0;
    while(!done)
    {
         done = true;
         viz.reset();
         for(int i = 1 ; i <= n ; i++)
             if(!dr[i] && cmgb(i))
             {
                 answer++;
                 done = 0;
             }
    }
    printf("%d\n",answer);
    for(int i = 1 ; i <= n ; i++)
        if(dr[i] != 0)
        printf("%d %d\n",i,dr[i]);
}

int main()
{
    read();
    Solution();
    return 0;
}