#include <iostream>
#include <cstdio>
#include <cstring>
using namespace std;

const int N=1111;

int n1,n2,k;


int mp[N][N],vis[N],link[N];
int vis2[N];
int v[N];

int dfs(int x)
{
    int i;
    vis2[x]=1;
    for(i=1; i<=n2; i++)
    {
        if(!mp[x][i]&&!vis[i])
        {
            vis[i]=1;
            if(link[i]==-1||dfs(link[i]))
            {
                link[i]=x;
                return 1;
            }
        }
    }
    return 0;
}

int main()

{

    int i,x,y,s;
    int cas = 0;
    while(scanf("%d%d%d",&n1,&n2,&k)&&n1){
        s=0;
        for(int i=1;i<=n1;i++){
            for(int j=1;j<=n2;j++){
               mp[i][j]=1;
            }
        }

        for(i=0; i<k; i++)
        {
            scanf("%d%d",&x,&y);
            mp[x][y]=0;
        }

        memset(link,-1,sizeof(link));

        for(i=1; i<=n1; i++)
        {
            memset(vis,0,sizeof(vis));
            if(dfs(i))
            s++;
        }

        memset(vis,0,sizeof(vis));
        memset(vis2,0,sizeof(vis2));
        memset(v,0,sizeof(v));

        for(int i=1;i<=n2;i++){
            v[link[i]]=1;
           //printf("link[%d] :%d\n",i,link[i]);
        }
        for(int i=1;i<=n1;i++){
            if(!v[i])
                dfs(i);
        }
        printf("%d",s);
        //左邊覆蓋點
        for(int i=1;i<=n1;i++){
            if(!vis2[i])
            printf(" r%d",i);
        }
        //右邊覆蓋點
        for(int i=1;i<=n2;i++){
            if(vis[i])
            printf(" c%d",i);
        }
        puts("");
    }
    return 0;
}

最小覆蓋點集模板