#include<cstdio>
#include<vector>
using namespace std;
vector<int>L[100100];
int n,m,k,i,j,a,b,ok,v[10100],l[10100],r[10100],nr;
FILE *f,*g;
int cupl(int nod){
    v[nod]=1;
    for(int i=0;i<L[nod].size();i++){
        if(r[L[nod][i]]==0){
            l[nod]=L[nod][i];
            r[L[nod][i]]=nod;
            return 1;
        }
    }
    for(int i=0;i<L[nod].size();i++){
        int a=L[nod][i];
        if(!v[r[a]]&&cupl(r[a])){
            l[nod]=L[nod][i];
            r[L[nod][i]]=nod;
            return 1;
        }
    }
    return 0;
}
int main(){
    f=fopen("cuplaj.in","r");
    g=fopen("cuplaj.out","w");
    fscanf(f,"%d%d%d",&n,&m,&k);
    for(i=1;i<=k;i++){
        fscanf(f,"%d%d",&a,&b);
        L[a].push_back(b);
    }
    if(n>m)
        m=n;
    do{
        ok=1;
        for(i=1;i<=m;i++){
            v[i]=0;
        }
        for(i=1;i<=m;i++){
            if(!l[i]&&cupl(i)){
                nr++;
                ok=0;
            }
        }
    }while(ok==0);
    fprintf(g,"%d\n",nr);
    for(i=1;i<=n;i++){
        if(l[i]!=0){
            fprintf(g,"%d %d\n",i,l[i]);
        }
    }



    fclose(f);
    fclose(g);
    return 0;
}