#include <cstdio>
#include <vector>
#include <queue>

using namespace std;

const int inf=1000000000;
vector<int> v[20010];
queue<int> q;
int cap[2010][2010],flow[2010][2010],tata[20010],sursa,dest;
char vaz[20010];

void add_edge(int x,int y,int c)
{
    v[x].push_back(y);
    v[y].push_back(x);
    cap[x][y]=c;
}

int bfs()
{
    for(int i=sursa;i<=dest;i++) vaz[i]=0;
    q.push(sursa);
    vaz[sursa]=1;
    while(!q.empty())
    {
        int nod=q.front();q.pop();
        for(vector<int>::iterator it=v[nod].begin();it!=v[nod].end();it++)
            if(!vaz[*it] && cap[nod][*it]>flow[nod][*it])
            {
                tata[*it]=nod;
                q.push(*it);
                vaz[*it]=1;
            }
    }
    return vaz[dest];
}

int main()
{
    freopen("cuplaj.in", "r", stdin);
    freopen("cuplaj.out", "w", stdout);
    int n,m,q,x,y,sol=0;
    scanf("%d%d%d",&n,&m,&q);
    sursa=0;dest=n+m+1;
    for(int i=1;i<=q;i++)
    {
        scanf("%d%d",&x,&y);
        add_edge(x,n+y,1);
    }
    for(int i=1;i<=n;i++) add_edge(0,i,1);
    for(int i=1;i<=m;i++) add_edge(n+i,dest,1);
    while(bfs())
    {
        for(vector<int>::iterator it=v[dest].begin();it!=v[dest].end();it++)
            if(cap[*it][dest]>flow[*it][dest])
            {
                tata[dest]=*it;
                int s=inf;
                for(int i=dest;i!=sursa;i=tata[i]) s=min(s,cap[tata[i]][i]-flow[tata[i]][i]);
                if(!s) continue;
                for(int i=dest;i!=sursa;i=tata[i])
                {
                    flow[tata[i]][i]++;
                    flow[i][tata[i]]--;
                }
                sol+=s;
            }
    }
    printf("%d\n",sol);
    for(int i=1;i<=n;i++)
        for(int j=1;j<=m;j++)
            if(flow[i][j+n]) printf("%d %d\n",i,j);
    return 0;
}