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#include<cstring>
#include<cstdio>
using namespace std;
const int N=2e4+100;
const int M=4e5+100;
const int inf=0x3f3f3f3f;
char *p1,*p2;
char buf[100];
#define nc() (p1==p2 && (p2=(p1=buf)+fread(buf,1,100,stdin),p1==p2)?EOF:*p1++)
inline void read(int &x){
x=0;
char ch=nc();
while(ch<48 || ch>57){
ch=nc();
}
while(ch>=48 && ch<=57){
x=(x<<3)+(x<<1)+ch-48;
ch=nc();
}
return ;
}
int tot;
int head[N];
struct edge{
int y;
int f;
int next;
}e[M];
int dep[N];
int gap[N];
int cur[N];
int last;
int dfn[N];
int low[N];
int cidx;
int col[N];
int nl,nr;
int n,m;
int s,t;
int bri_sta;
int top;
int pri[N];
int q[M];
int stk[M];
int _top;
inline int max(int a,int b){return a>b?a:b;}
inline int min(int a,int b){return a<b?a:b;}
inline int ops(int x){return x^1;}
void init(){
tot=0;
memset(head,-1,sizeof(head));
s=0;
t=nl+nr+1;
return ;
}
inline void add(int x,int y,int f){
e[tot].y=y;
e[tot].f=f;
e[tot].next=head[x];
head[x]=tot++;
return ;
}
inline void make(int x,int y,int f){
add(x,y,f);
add(y,x,0);
return ;
}
void debug(){
for(int i=0;i<tot;i+=2){
int x=e[ops(i)].y;
int y=e[i].y;
int f=e[i].f;
printf("%d %d %d \n",x,y,f);
}
return ;
}
void bfs(int start,int to){
memset(dep,-1,sizeof(dep));
int hh=0;
int tt=1;
q[hh]=to;
dep[to]=0;
gap[0]=1;
while(hh!=tt){
int x=q[hh++];
if(hh==M)hh=0;
for(int i=head[x];~i;i=e[i].next){
int y=e[i].y;
if(dep[y]!=-1)continue;
dep[y]=dep[x]+1;
gap[dep[y]]++;
q[tt++]=y;
if(tt==M)tt=0;
}
}
return ;
}
int find(int x,int to,int lim){
if(x==to)return lim;
int flow=0;
for(int i=cur[x];~i;i=e[i].next){
int y=e[i].y;
int f=e[i].f;
cur[x]=i;
if(!f)continue;
if(dep[y]+1==dep[x]){
int t=find(y,to,min(f,lim-flow));
if(t>0){
e[i].f-=t;
e[ops(i)].f+=t;
flow+=t;
}
if(flow==lim)return flow;
}
}
gap[dep[x]]--;
if(!gap[dep[x]])dep[s]=n+1;
dep[x]++;
gap[dep[x]]++;
return flow;
}
int ISAP(int start,int to){
int flow=0;
bfs(start,to);
while(dep[start]<=n+1){
memcpy(cur,head,sizeof(head));
flow+=find(start,to,inf);
}
return flow;
}
void tarjan(int x){
last++;
dfn[x]=last;
low[x]=last;
stk[++_top]=x;
for(int i=head[x];~i;i=e[i].next){
if(!e[i].f)continue;
int y=e[i].y;
if(!dfn[y]){
tarjan(y);
low[x]=min(low[x],low[y]);
}
else if(!col[y])low[x]=min(low[x],dfn[y]);
}
if(dfn[x]==low[x]){
cidx++;
while(_top){
int t=stk[_top--];
col[t]=cidx;
if(t==x)break;
}
}
return ;
}
int main(){
read(nl);
read(nr);
read(m);
n=nl+nr+2;
init();
for(int i=1;i<=nl;i++)make(s,i,1);
for(int i=1;i<=nr;i++)make(i+nl,t,1);
bri_sta=tot;
for(int i=1;i<=m;i++){
int x,y;
read(x);
read(y);
y+=nl;
make(x,y,1);
}
int ans=ISAP(s,t);
for(int i=1;i<=n;i++)if(!dfn[i])tarjan(i);
for(int i=bri_sta;i<tot;i+=2){
int x=e[ops(i)].y;
int y=e[i].y;
int f=e[i].f;
if(f && col[x]!=col[y]){
pri[++top]=(i-bri_sta)/2+1;
}
}
printf("%d\n",top);
for(int i=1;i<=top;i++){
printf("%d ",pri[i]);
}
putchar('\n');
return 0;
}
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