/****************************************************
    > File Name: hungry.cpp
    > Author: Yuji CAO
    > Mail: [email protected] 
    > Created Time: 日  6/11 18:29:58 2017
 *****************************************************/

#include<map>
#include<vector>
#include<unordered_set>
 

#include<unordered_map>
#include<list>
#include<queue>
#include<deque>
#include<stack>
#include<iostream>
#include<set>
using namespace std;

bool rematch_for_node(vector<vector<int> >& link_left_2_right, int left, vector<int>& match, unordered_set
 
<int>& visited) {
    for (int j : link_left_2_right[left]) {
        if (visited.count(j) != 0) continue;
        if (match[j] != -1) {
            visited.insert(j);
            bool rematch = rematch_for_node(link_left_2_right, match[j], match, visited);
            if (rematch) {
                match[j] = left;
                return
 
 true;
            }
        } else {
            match[j] = left;
            return true;
        }
    }
    return false;
}

int max_match(vector<vector<int> >& link_left_2_right, int m, vector<int>& match) {
    int res = 0;
    match.resize(m, -1);
    for (int i = 0; i < link_left_2_right.size(); ++i) {
        unordered_set<int> visited;
        bool tmp = rematch_for_node(link_left_2_right, i, match, visited);
        if (tmp) res++;
    }
    return res;
}

int main() {
    int n,m;
    cin>>n>>m;
    int n_edge = 0;
    cin>>n_edge;
    vector<vector<int> > link_left_2_right(n, vector<int>());
    for (int i = 1; i <= n_edge; ++i) {
        int l, r;
        cin>>l>>r;
        link_left_2_right[l].push_back(r);
    }
    vector<int> match;
    int ans = max_match(link_left_2_right, m, match);
    cout<<"answer:\t"<<ans<<endl;
    for (int i = 0; i < match.size(); ++i) {
        cout<<i<<"\t"<<match[i]<<endl;
    }
    return 0;
}