#include<iostream>
#include<cstdio>
#include<algorithm>
#include<vector>
#include<queue>
#include<map>
#include<set>
#include<array>
#include<ctime>
#define fi first
#define se second
#define mp make_pair
#define pb emplace_back
using namespace std;
typedef long long ll;
template<typename T>
T &read(T &r){
	r=0;bool w=0;char ch=getchar();
	while(ch<'0'||ch>'9')w=ch=='-'?1:0,ch=getchar();
	while(ch>='0'&&ch<='9')r=r*10+ch-'0',ch=getchar();
	return r=w?-r:r;
}
const int N=5000010;
const int inf=0x7fffffff;
int tot,S,T;
int head[N],cur[N],dis[N],ent=1;
int nxt[N*3],to[N*3],fl[N*3];
inline void adde(int x,int y,int w){
	++ent;
	nxt[ent]=head[x];to[ent]=y;fl[ent]=w;
	head[x]=ent;
	++ent;
	nxt[ent]=head[y];to[ent]=x;fl[ent]=0;
	head[y]=ent;
}
int bfs(){
	for(int i=1;i<=tot;i++)dis[i]=inf,cur[i]=head[i];
	dis[S]=0;queue<int>q;q.push(S);
	while(!q.empty()){
		int x=q.front();q.pop();
		for(int i=head[x];i;i=nxt[i]){
			int v=to[i],w=fl[i];
			if(w){
				if(dis[v]>dis[x]+1){
					dis[v]=dis[x]+1;
					if(v==T)return 1;
					q.push(v);
				}
			}
		}
	}
	return dis[T]!=inf;
}
int dfs(int x,int flow){
	if(x==T)return flow;
	int flo=0;
	for(int i=cur[x];i&&flo<flow;i=nxt[i]){
		cur[x]=i;
		int v=to[i],w=fl[i];
		if(dis[v]==dis[x]+1&&w){
			int wfl=dfs(v,min(flow-flo,w));
//			if(wfl==0)dis[v]=-1;
			flo+=wfl;fl[i]-=wfl;
			fl[i^1]+=wfl;
		}
	}
	return flo;
}
int A,B,m;
int main(){
//	freopen("data.in","r",stdin);
//	freopen("data.out","w",stdout);
	read(A);read(B);read(m);
	S=A+B+1;T=tot=A+B+2;
	for(int i=1,u,v;i<=m;i++){
		read(u);read(v);
		adde(u,A+v,1);
	}
	for(int i=1;i<=A;i++)adde(S,i,1);
	for(int i=1;i<=B;i++)adde(i+A,T,1);
	int s=0;
	while(bfs()&&1.0*clock()/CLOCKS_PER_SEC<=3.3){
		cerr<<1<<'\n';
		s+=dfs(S,inf);
	}
	cout<<s<<'\n';
	for(int i=1;i<=A;i++){
		for(int j=head[i];j;j=nxt[j]){
			if(fl[j]==0&&to[j]!=S){
				cout<<(j+1)/2<<'\n';
			}
		}
	}
	return 0;
}