BM_RMT

#include <iostream>#include <memory.h>using namespace std;#define REP(i,N)	for(int i=0;i<(N);++i)#define FOR(i,a,b)	for(int i=(a);i<=(b);++i)#define FORD(i,a,b)	for(int i=(a);i>=(b);--i)#define MAXNODES 1005bool adjacent[MAXNODES][MAXNODES];//Structures required for finding the maximum matchingint matching[2][MAXNODES];int path[2*MAXNODES];bool visited[2][MAXNODES];int L;        //Length of the augmenting path foundint N, K;    //Number of nodes on side 0 and 1 respectivelybool find_augmenting_path(int node, int side){	visited[side][node] = true;	path[L++] = node;	if(side == 0) {		FOR(i,1,K) {			if(!visited[1][i] && adjacent[node][i] && matching[0][node]!=i) 				if(find_augmenting_path(i,1)) return true;		}	} else {		if(matching[1][node] == 0)			return true;		else {			if(!visited[0][matching[1][node]])				if(find_augmenting_path(matching[1][node],0)) return true;		}	}	--L;	return false;}int main(){	int C, c, e;	scanf("%d %d %d", &N, &K, &C);	while(C--) {		scanf("%d %d", &c, &e);		adjacent[c][e] = true;	}	//Try finding an augmenting path till none can be found	while(1) {		bool more_augmenting_path = false;		memset(visited,0,sizeof(visited));    //Set all nodes as NOT visited		L = 0;		FOR(i,1,N) {			if(matching[0][i] == 0) {    //Find first unmatched node				if(find_augmenting_path(i,0)) {					more_augmenting_path = true;					break;				}			}		}		if(more_augmenting_path) {			for(int i = 0 ; i < L ; i+=2) {				matching[0][path[i]] = path[i+1];				matching[1][path[i+1]] = path[i];			}		} else {			break;		}	}	int count = 0;	FOR(i,1,N) if(matching[0][i] != 0) ++count;	printf("%d\n", count);	FOR(i,1,N) if(matching[0][i] != 0) printf("%d %d\n", i, matching[0][i]);	return 0;}