#include <cmath>
#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
#define lowbit(x) ((x)&-(x))
using namespace std;
struct node{
	int x,y,id;
}a[100005];
bool cmp(node a,node b)
{
	return a.x==b.x?a.y>b.y:a.x<b.x;
}
int Ans1[100005],Ans2[100005],f[100005],g[100005],vis[100005],n,ans1num,ans2num,s[100005],ans,ls[100005];
bool cmp2(int a,int b)
{
	return f[a]<f[b];
}
bool ans1[100005];
void add(int p,int x)
{
	p=lower_bound(ls+1,ls+n+1,p)-ls;
	for(;p<=n;p+=lowbit(p))
	{
		s[p]=max(s[p],x);
	}
}
int get(int p)
{
	p=lower_bound(ls+1,ls+n+1,p)-ls-1;
	int nowans=0;
	for(;p;p-=lowbit(p))
	{
		nowans=max(nowans,s[p]);
	}
	return nowans;
}
int main()
{
	freopen("input.txt","r",stdin);
	freopen("output.txt","w",stdout);
	scanf("%d",&n);
	for(int i=1;i<=n;++i)
	{
		scanf("%d%d",&a[i].x,&a[i].y);
		a[i].id=i;
		ls[i]=a[i].y;
	}
	sort(ls+1,ls+n+1);
	sort(a+1,a+n+1,cmp);
	for(int i=1;i<=n;++i)
	{
		f[i]=get(a[i].y)+1;
		add(a[i].y,f[i]);
		ans=max(ans,f[i]);
	}
	for(int i=n;i;--i)
	{
		if(f[i]==ans||(vis[f[i]+1]&&a[i].y<g[f[i]+1]))
		{
			ans1[i]=1;
			if(vis[f[i]]==0)
			{
				g[f[i]]=a[i].y;
				vis[f[i]]=1;
			}
			else
			{
				g[f[i]]=max(g[f[i]],a[i].y);
			}		
		}
	}
	for(int i=1;i<=n;++i)
	if(ans1[i])
	{
		Ans1[++ans1num]=i;
	}
	sort(Ans1+1,Ans1+ans1num,cmp2);
	for(int i=1;i<=ans1num;++i)
	{
		if(f[Ans1[i]]!=f[Ans1[i-1]]&&f[Ans1[i]]!=f[Ans1[i+1]])
		{
			Ans2[++ans2num]=a[Ans1[i]].id;
		}
	}
	for(int i=1;i<=ans1num;++i)
	Ans1[i]=a[Ans1[i]].id;
	sort(Ans1+1,Ans1+ans1num+1);
	sort(Ans2+1,Ans2+ans2num+1);
	
	
	printf("%d ",ans1num);
	for(int i=1;i<ans1num;++i)
		printf("%d ",Ans1[i]);
	if(ans1num) printf("%d\n",Ans1[ans1num]);
	printf("%d ",ans2num);
	for(int i=1;i<ans2num;++i)
		printf("%d ",Ans2[i]);
	if(ans2num)printf("%d\n",Ans2[ans2num]);
	return 0;
}