#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N=4e6+5,INF=0x3f3f3f3f;
int n1,n2,m,h[N],hh[N],cnt=1,S,T,dep[N],q[N],id[N],tmp[N],top;
struct edge {int to,nxt,f;}e[N*3];
char buf[1<<20],*p1,*p2;
#define gc() (p1==p2&&(p2=(p1=buf)+fread(buf,1,1<<20,stdin),p1==p2)?EOF:*p1++)
void Addedge(int x,int y,int f)
{
	e[++cnt]=(edge){y,h[x],f},h[x]=cnt;
	e[++cnt]=(edge){x,h[y],0},h[y]=cnt;
}
bool bfs()
{
	memset(dep,0,sizeof(dep)),dep[S]=1;
	int l=1,r=1; q[1]=S;
	while(l<=r)
	{
		int x=q[l++];
		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[++r]=y;
		}
	}
	return dep[T];
}
int dfs(int x,int f)
{
	if(x==T||!f) return f;
	int res=0; if(hh[x]==h[x]) tmp[++top]=x;
	for(int &i=hh[x];i;i=e[i].nxt) if(e[i].f)
	{
		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;
}
inline int read()
{
	int s=0; char c=gc();
	while(c<'0'||c>'9') c=gc();
	while(c>='0'&&c<='9') s=s*10+(c^48),c=gc();
	return s;
}
inline void write(int x)
{
	if(!x) {putchar('0'); return;}
	static int s[11],t=0;
	while(x) s[++t]=x%10,x/=10;
	while(t) putchar(s[t--]+'0');
}
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);
	n1=read(),n2=read(),m=read(),S=n1+n2+1,T=S+1;
	for(int i=1,x,y;i<=m;i++) x=read(),y=read(),Addedge(x,y+n1,1),id[i]=cnt-1;
	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=19,res=0; memcpy(hh,h,sizeof(h));
	while(t--&&bfs())
	{
		res+=dfs(S,INF);
		while(top--) hh[tmp[top]]=h[tmp[top]];
	}
	write(res),puts("");
	for(int i=1;i<=m;i++) if(!e[id[i]].f) write(i),puts("");
	return 0;
}