#include <algorithm>
#include <vector>
#include <bitset>
using namespace std;

#define pb push_back
#define DIM 10005

vector <int> g[DIM];
int l[DIM],r[DIM];
bitset <DIM> viz;
int n,m,e,nrt;

void read ()
{
    int i,x,y;

    scanf ("%d%d%d",&n,&m,&e);
    for (i=1; i<=e; ++i)
    {
        scanf ("%d%d",&x,&y);
        g[x].pb (y);
    }
}

int pairup (int nod)
{
    vector <int> :: iterator it;

    if (viz[nod])
        return 0;

    viz[nod]=1;
    for (it=g[nod].begin (); it!=g[nod].end (); ++it)
        if (!r[*it])
        {
            l[nod]=*it;
            r[*it]=nod;

            return 1;
        }
    for (it=g[nod].begin (); it!=g[nod].end (); ++it)
        if (pairup (r[*it]))
        {
            l[nod]=*it;
            r[*it]=nod;

            return 1;
        }

    return 0;
}

void solve ()
{
    int i,ok;

    do
    {
        ok=0;
        viz.reset ();
        for (i=1; i<=n; ++i)
            if (!l[i] && pairup (i))
            {
                ok=1;
                ++nrt;
            }
    }
    while (ok);
}

void print ()
{
    int i;

    printf ("%d\n",nrt);
    for (i=1; i<=n; ++i)
        if (l[i])
            printf ("%d %d\n",i,l[i]);
}

int main ()
{
    freopen ("cuplaj.in","r",stdin);
    freopen ("cuplaj.out","w",stdout);

    read ();
    solve ();
    print ();

    return 0;
}