#include <bits/stdc++.h>
using namespace std;
const int inf=2e9,N=1e7+5,M=1e7+5;
//const int inf=0x3f3f3f3f,N=1e3+5,M=1e3+5;

int head[N],ver[M],edge[M],Next[M],d[N],id[N];
int s,t,tot=1,maxflow,flow;
void add(int x,int y,int z,int k) {
    ver[++tot]=y,edge[tot]=z,Next[tot]=head[x],head[x]=tot,id[tot]=k;
    ver[++tot]=x,edge[tot]=0,Next[tot]=head[y],head[y]=tot,id[tot]=0;
}
queue<int> q;
int bfs() {
    for(int i=1;i<=t;i++)d[i]=0;
    while(q.size())q.pop();
    q.push(s),d[s]=1;
    while(q.size()) {
        int x=q.front();
        q.pop();
        for(int i=head[x];i;i=Next[i])
            if(edge[i]&&!d[ver[i]]) {
                q.push(ver[i]),d[ver[i]]=d[x]+1;
                if(ver[i]==t)return 1;
            }
    }
    return 0;//分层，判断是否可增广
}
int vis[N];
int dinic(int x,int flow) {
    if(x==t) return flow;
    int rest=flow,k;//rest现在还有多少可流
    for(int i=head[x];i;i=Next[i]) 
        if(edge[i]&&d[ver[i]]==d[x]+1) {//必须跳到下一层
            k=dinic(ver[i],min(rest,edge[i]));
//            if(!k) d[ver[i]]=0;
            if(k) {
            	edge[i]-=k,edge[i^1]+=k,rest-=k;
            	vis[id[i]]=1;
            	vis[id[i^1]]=0;
            	if(!rest) return flow;
            }
        }
    return flow-rest;//用了多少流
}
int main(){
	int n1,n2,m;
	scanf("%d%d%d",&n1,&n2,&m);
	s=n1+n2+1;
	t=s+1;
	for(int i=1;i<=m;i++) {
		int u,v;
		scanf("%d%d",&u,&v);
		add(u,v+n1,1,i);
	}
	for(int i=1;i<=n1;i++) {
		add(s,i,1,0);
	}
	for(int i=1;i<=n2;i++) {
		add(i+n1,t,1,0);
	}
    while(bfs()) maxflow+=dinic(s,inf);
    printf("%d\n",maxflow);
    for(int i=1;i<=m;i++) {
    	if(vis[i]) {
    		printf("%d\n",i);
    	}
    }
    return 0;
}