#include<cstdio>
#include<vector>
#include<cstring>
using namespace std;
FILE*in=fopen("cuplaj.in","r");
FILE*out=fopen("cuplaj.out","w");
const int NMAX=10007;
int n,m,e,i,x,y,ct,ctt;
vector<int> adjl[NMAX],adjr[NMAX];
int l[NMAX],r[NMAX];
bool bl[NMAX],br[NMAX];
bool cuplaj(int nod)
{
    if(bl[nod]==1)
    {
        return 0;
    }
    bl[nod]=1;
    for(auto w:adjl[nod])
    {
        if(r[w]==0)
        {
            l[nod]=w;
            r[w]=nod;
            return 1;
        }
    }
    for(auto w:adjl[nod])
    {
        if(cuplaj(r[w])==1)
        {
            l[nod]=w;
            r[w]=nod;
            return 1;
        }
    }
    return 0;
}
int main()
{
    fscanf(in,"%d%d%d",&n,&m,&e);
    for(i=1;i<=e;i++)
    {
        fscanf(in,"%d%d",&x,&y);
        adjl[x].push_back(y);
        adjr[y].push_back(x);
    }
    while(true)
    {
        ctt=ct;
        memset(bl,0,sizeof(bl));
        for(i=1;i<=n;i++)
        {
            if(l[i]==0)
            {
                if(cuplaj(i)==1)
                {
                    ct++;
                }
            }
        }
        if(ctt==ct)
        {
            break;
        }
    }
    fprintf(out,"%d\n",ct);
    for(i=1;i<=n;i++)
    {
        if(l[i]!=0)
        {
            fprintf(out,"%d %d\n",i,l[i]);
        }
    }
}