#include <stdio.h>

#define DIM 2005
#define oo 1<<31-1

struct nod {int x;
            nod *urm;} *lst[DIM];
int c[DIM][DIM],f[DIM][DIM];
int q[DIM],t[DIM],viz[DIM];
int n,m,e,s,d,minim,cuplaj;

void add (int a,int b)
{
    nod *p=new nod;

    p->x=b;
    p->urm=lst[a];
    lst[a]=p;
}

void read ()
{
    freopen ("cuplaj.in","r",stdin);
    int i,x,y;

	scanf ("%d%d%d",&n,&m,&e);
	s=0; d=n+m+1;
    for (i=1; i<=e; ++i)
    {
        scanf ("%d%d",&x,&y);
        add (s,x); add (x,s);
        add (x,y+n); add (y+n,x);
        add (y+n,d); add (d,y+n);
        c[s][x]=c[x][y+n]=c[y+n][d]=1;
    }
}

int bf ()
{
    nod *p;
    int st,dr,i;

    for (i=0; i<=d; ++i)
        t[i]=0;
    for (q[st=dr=1]=s; st<=dr; ++st)
        for (p=lst[q[st]]; p; p=p->urm)
            if (!t[p->x] && c[q[st]][p->x]>f[q[st]][p->x])
            {
                t[p->x]=q[st];
                q[++dr]=p->x;
            }
    return t[d];
}

int min (int a,int b)
{
    if (a<b)
        return a;
    return b;
}

void solve ()
{
    int i,j;

    for ( ; bf (); )
		for (i=0; i<=d; ++i)
		    if (t[i]>0 && c[i][d]-f[i][d]>0)
		    {
				minim=c[i][d]-f[i][d];
    			for (j=i; j!=0; j=t[j])
    				minim=min (minim,c[t[j]][j]-f[t[j]][j]);
                f[i][d]+=minim;
                f[d][i]-=minim;
    			for (j=i; j!=0; j=t[j])
                {
                    f[t[j]][j]+=minim;
                    f[j][t[j]]-=minim;
                }     
                if (minim)
                    ++cuplaj;
        	}
}

void print ()
{
    freopen ("cuplaj.in","r",stdin);
    freopen ("cuplaj.out","w",stdout);
    int i,x,y;
    
	printf ("%d\n",cuplaj);
    scanf ("%d%d%d",&n,&m,&e);
    for (i=1; i<=e; ++i)
    {
        scanf ("%d%d",&x,&y);
		if (f[x][y+n]!=0)
            printf ("%d %d\n",x,y);
    }
}

int main ()
{
    read ();
	solve ();
    print ();

    return 0;
}