#include<bits/stdc++.h>
#define N 200010
#define inf 0x3f3f3f3f
#define For(i,a,b) for(register int i=a;i<=b;i++)
#define Edge(i,x) for(register int i=head[x],to=e[i].t;i;i=e[i].nx,to=e[i].t)
#define EDge(i,x) for(register int i=lnk[x],to=e[i].t;i;i=e[i].nx,to=e[i].t)
using namespace std;
int head[N],x[N],y[N];
int lnk[N],num=1,dist[N],id[N];
bool exist[N],vis[N];
struct E{int nx,t,cap;}e[N<<1];
queue<int> q;
inline void add(int f,int t,int c){e[++num]=(E){head[f],t,c};head[f]=num;}
inline void bio_add(int f,int t,int c){add(f,t,c),add(t,f,0);}
inline int read()
{
    register int x=0,c=getchar();
    while(!isdigit(c)) c=getchar();
    while(isdigit(c)) x=(x<<1)+(x<<3)+(c^48),c=getchar();
    return x;
}

inline bool BFS(int st,int en)
{
    For(i,0,en) dist[i]=-1,lnk[i]=head[i];
    dist[st]=0,q.push(st);
    while(!q.empty())
    {
        int k=q.front();q.pop();
        Edge(i,k) if(e[i].cap && dist[to] == -1)
            dist[to]=dist[k]+1,q.push(to);
    } 
    return dist[en]!=-1;
}

inline int dinic(int x,int t,int rest)
{
    if(x == t || !rest) return rest;
    int res=0;vis[x]=true;
    EDge(i,x)
    {
        lnk[x]=i;
	    if(!vis[to] && e[i].cap && dist[to] == dist[x]+1)
	    {
            int get=dinic(to,t,min(e[i].cap,rest-res));
            if(!get) continue;
	        e[i].cap-=get,e[i^1].cap+=get,res+=get;
	        if(res == rest) break;
	    }
    }vis[x]=false;
    return res;
}

inline int max_flow(int st,int en)
{
    int ans=0;
    while(BFS(st,en))
    {
        int nw=dinic(st,en,inf);
	    while(nw) ans+=nw,nw=dinic(st,en,inf);
    }
    return ans;
}

int main()
{
    int L=read(),R=read(),m=read();
    int s=0,t=L+R+1;
    For(i,1,L) bio_add(s,i,1);
    For(i,1,R) bio_add(L+i,t,1);
    For(i,1,m)
    {
        x[i]=read()+1,y[i]=read()+1;
	    bio_add(x[i],L+y[i],1),id[i]=num;
    }printf("%d\n",max_flow(s,t));
    For(i,1,m) if(e[id[i]].cap) printf("%d %d\n",x[i]-1,y[i]-1);
    return 0;
}