#include<cstdio>
#include<vector>
using namespace std;

int n,m,e,x,y,i,gata,cuplaj,cd[10010],ci[10010],viz[10010],creste(int);
vector<int> V[10010];

void read(),solve();

int main()
{
	read();
	solve();
	
	return 0;
}

void read()
{
	freopen("cuplaj.in","r",stdin);
	freopen("cuplaj.out","w",stdout);
	scanf("%d%d%d",&n,&m,&e);
	for(;e;e--)
	{
		scanf("%d%d",&x,&y);
		V[x].push_back(y);
	}
}

void solve()
{
	while(!gata)
	{
		gata=1;
		for(i=1;i<=n;i++)viz[i]=0;
		for(i=1;i<=n;i++)
		{
			if(!cd[i]&&creste(i))
			{
				gata=0;
				cuplaj++;
			}
		}
	}
	printf("%d\n",cuplaj);
	for(i=1;i<=n;i++)
		if(cd[i])printf("%d %d\n",i,cd[i]);
}

int creste(int x)
{
	vector<int>::iterator it;
	if(viz[x])return 0;
	viz[x]=1;
	for(it=V[x].begin();it!=V[x].end();it++)
	{
		if(!ci[*it]){cd[x]=*it;ci[*it]=x;return 1;}
	}
	for(it=V[x].begin();it!=V[x].end();it++)
	{
		if(creste(ci[*it])){cd[x]=*it;ci[*it]=x;return 1;}
	}
	return 0;
}