#include<cstdio>
#include<vector>
#include<cstring>
using namespace std;
FILE*in=fopen("cuplaj.in","r");
FILE*out=fopen("cuplaj.out","w");
int n,m,e,i,j,x,y,ct;
vector<int> v[10004];
int r[10004],l[10004];
bool b[10004];
bool cuplaj(int nod)
{
    if(b[nod]==1)
    {
        return 0;
    }
    b[nod]=1;
    for(int t=0;t<v[nod].size();t++)
    {
        if(l[v[nod][t]]==0)
        {
            l[v[nod][t]]=nod;
            r[nod]=v[nod][t];
            return 1;
        }
    }
    for(int t=0;t<v[nod].size();t++)
    {
        if(cuplaj(l[v[nod][t]])==1)
        {
            l[v[nod][t]]=nod;
            r[nod]=v[nod][t];
            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);
        v[x].push_back(y);
    }
    for(i=1;i<=n;i++)
    {
        memset(b,0,sizeof(b));
        if(cuplaj(i)==1)
        {
            ct++;
        }
    }
    fprintf(out,"%d\n",ct);
    for(i=1;i<=n;i++)
    {
        if(r[i]!=0)
        {
            fprintf(out,"%d %d\n",i,r[i]);
        }
    }
}