#include <iostream>
#include <vector>
#include <queue>
#include <stack>
#include <fstream>
#include <cstring>
#include <bitset>
#include <unordered_map>
using namespace std;

ofstream G("cuplaj.out");

const int N = 20010;

int n,m,e,dad[N];
vector<pair<int,int> > edges;
vector<int> v[N];
unordered_map<int,int> cap[N];

const int Buffer=1<<13;
char Buff[Buffer]; int Next=0;

#define F stdin

int get_int()
{
    int Nbr=0;
    while( Buff[Next]<'0' || '9'<Buff[Next] )
        if ( ++Next >= Buffer ) fread(Buff,Buffer,1,F), Next=0;
    while ( '0'<=Buff[Next] && Buff[Next]<='9' )
    {
        Nbr=Nbr*10+Buff[Next]-'0';
        if ( ++Next >= Buffer ) fread(Buff,Buffer,1,F), Next=0;
    }
    return Nbr;
}


int go()
{
    memset(dad,0,sizeof(dad));
    dad[1] = -1;

    queue<int> vt;
    vt.push(1);
    while ( !vt.empty() )
    {
        int x = vt.front();
        vt.pop();

        for (int i=0;i<int(v[x].size());++i)
        {
            int y = v[x][i];
            if ( dad[y] == 0 && cap[x][y] > 0 )
            {
                dad[y] = x;
                vt.push(y);
            }
        }
    }

    return dad[n];
}

int main()
{
    freopen("cuplaj.in","r",stdin);
    n = get_int();
    m = get_int();
    e = get_int();
    for (int i=1,x,y;i<=e;++i)
    {
        x = get_int();
        y = get_int();
        x ++;
        y += n+1;
        cap[x][y] = 1;
        v[x].push_back(y);
        v[y].push_back(x);
        edges.push_back( make_pair(x,y) );
    }
    for (int i=1;i<=n;++i) v[1].push_back(i+1) , cap[1][i+1] = 1;
    for (int i=1;i<=m;++i)
    {
        v[i+n+1].push_back(n+m+2);
        v[n+m+2].push_back(n+i+1);
        cap[i+n+1][n+m+2] = 1;
    }
    int an = n;
    n = n + m + 2;

    int flow = 0;
    while ( go() )
        for (int i=0;i<int(v[n].size());++i)
        {
            int x = v[n][i];
            if ( dad[x] != 0 && cap[x][n] > 0 )
            {
                int cp = cap[x][n];
                for (int j=x;j!=1;j=dad[j]) cp = min(cp,int(cap[dad[j]][j]));
                if ( cp == 0 ) continue;
                for (int j=x;j!=1;j=dad[j])
                {
                    cap[dad[j]][j] = 0;
                    cap[j][dad[j]] = 1;
                }
                cap[x][n] = 0;
                flow += cp;
            }
        }
    G<<flow<<'\n';
    for (int i=0;i<e;++i)
        if ( cap[edges[i].second][edges[i].first] )
            G<<edges[i].first-1<<' '<<edges[i].second-an-1<<'\n';
}