#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N=2e6+5,INF=0x3f3f3f3f;
int n1,n2,m,h[N],hh[N],cnt=1,S,T,dep[N];
struct edge {int to,nxt,f,id;}e[N*4];
void Addedge(int x,int y,int f,int id=0)
{
	e[++cnt]=(edge){y,h[x],f,id},h[x]=cnt;
	e[++cnt]=(edge){x,h[y],0,id},h[y]=cnt;
}
bool bfs()
{
	memset(dep,0,sizeof(dep));
	queue<int>q; dep[S]=1,q.push(S);
	while(!q.empty())
	{
		int x=q.front(); q.pop();
		for(int i=h[x];i;i=e[i].nxt) if(e[i].f)
		{
			int y=e[i].to;
			if(!dep[y]) dep[y]=dep[x]+1,q.push(y);
		}
	}
	return dep[T];
}
int dfs(int x,int f)
{
	if(x==T||!f) return f;
	int res=0;
	for(int &i=hh[x];i;i=e[i].nxt)
	{
		int y=e[i].to;
		if(dep[x]+1==dep[y])
		{
			int d=dfs(y,min(e[i].f,f-res));
			if(d) e[i].f-=d,e[i^1].f+=d,res+=d;
			if(res==f) return res;
		}
	}
	return res;
}
int main()
{
#ifdef LOCAL
	freopen("1.in","r",stdin);
	freopen("1.out","w",stdout);
	freopen("1.err","w",stderr);
#endif
	ios::sync_with_stdio(0),cin.tie(0);
	cin>>n1>>n2>>m,S=n1+n2+1,T=S+1;
	for(int i=1,x,y;i<=m;i++) cin>>x>>y,Addedge(x,y+n1,1,i);
	for(int i=1;i<=n1;i++) Addedge(S,i,1);
	for(int i=1;i<=n2;i++) Addedge(i+n1,T,1);
	int t=20,res=0;
	while(t--&&bfs()) memcpy(hh,h,sizeof(h)),res+=dfs(S,INF);
	cout<<res<<"\n";
	vector<int>ans;
	for(int x=1;x<=n1;x++)
		for(int i=h[x];i;i=e[i].nxt) if(e[i].id&&!e[i].f) ans.emplace_back(e[i].id);
	for(auto x:ans) cout<<x<<"\n";
	return 0;
}