Problem: You are given n pairs of integers (a_1, b_1), (a_2, b_2), …, (a_n, b_n). All of the integers in the pairs are distinct and are in the range from 1 to 2 ⋅ n inclusive.

Let's call a sequence of integers x_1, x_2, …, x_{2k} good if either 

  * x_1 < x_2 > x_3 < … < x_{2k-2} > x_{2k-1} < x_{2k}, or 
  * x_1 > x_2 < x_3 > … > x_{2k-2} < x_{2k-1} > x_{2k}. 



You need to choose a subset of distinct indices i_1, i_2, …, i_t and their order in a way that if you write down all numbers from the pairs in a single sequence (the sequence would be a_{i_1}, b_{i_1}, a_{i_2}, b_{i_2}, …, a_{i_t}, b_{i_t}), this sequence is good.

What is the largest subset of indices you can choose? You also need to construct the corresponding index sequence i_1, i_2, …, i_t.

Input

The first line contains single integer n (2 ≤ n ≤ 3 ⋅ 10^5) — the number of pairs.

Each of the next n lines contain two numbers — a_i and b_i (1 ≤ a_i, b_i ≤ 2 ⋅ n) — the elements of the pairs.

It is guaranteed that all integers in the pairs are distinct, that is, every integer from 1 to 2 ⋅ n is mentioned exactly once.

Output

In the first line print a single integer t — the number of pairs in the answer.

Then print t distinct integers i_1, i_2, …, i_t — the indexes of pairs in the corresponding order.

Examples

Input


5
1 7
6 4
2 10
9 8
3 5


Output


3
1 5 3


Input


3
5 4
3 2
6 1


Output


3
3 2 1

Note

The final sequence in the first example is 1 < 7 > 3 < 5 > 2 < 10.

The final sequence in the second example is 6 > 1 < 3 > 2 < 5 > 4.

Solution (in JAVA):

Solution:
import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.lang.reflect.Array;
import java.math.BigInteger;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.BitSet;
import java.util.Collections;
import java.util.Comparator;
import java.util.Deque;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.PriorityQueue;
import java.util.Queue;
import java.util.Random;
import java.util.Set;
import java.util.Stack;
import java.util.StringTokenizer;
import java.util.TreeMap;
import java.util.TreeSet;

public class q5 {
	
	
	public static void main(String[] args) throws IOException {
		
		Reader.init(System.in);
		PrintWriter out=new PrintWriter(System.out);
		StringBuffer output=new StringBuffer("");
		int n=Reader.nextInt();
		ArrayList<NoD> t1=new ArrayList<NoD>(),t2=new ArrayList<NoD>();
		for(int i=1;i<=n;i++) {
			int a=Reader.nextInt();int b=Reader.nextInt();
			NoD ta=new NoD(a,b,i);
			if(a<b) t1.add(ta);
			else t2.add(ta);
		}
		Collections.sort(t1,new Comparator<NoD>() {
			public int compare(NoD a,NoD b) {
				return b.b-a.b;
			}
		});
		Collections.sort(t2,new Comparator<NoD>() {
			public int compare(NoD a,NoD b) {
				return a.b-b.b;
			}
		});
		
		ArrayList<Integer> a1=new ArrayList<Integer>();
		ArrayList<Integer> a2=new ArrayList<Integer>();
		int h=Integer.MAX_VALUE;
		for(NoD a:t1) {
			if(h>a.a) {
				a1.add(a.c);
				h=a.b;
			}
		}
		int l=0;
		for(NoD a:t2) {
			if(l<a.a) {
				l=a.b;
				a2.add(a.c);
			}
		}
		if(a1.size()>=a2.size()) {
			out.println(a1.size());
			for(int i:a1) {
				out.print(i);out.print(" ");
			}
		}
		else {
			out.println(a2.size());
			for(int i:a2) {
				out.print(i);out.print(" ");
			}
		}
		out.flush();
	}
}



class NoD{
	int a;int b, c;
	String s;

	NoD(int aa,int bb,int cc){
		a=aa;b=bb;c=cc;
		s=a+" "+b;
		
	}
	
//	NoD(int aa,int bb,int cc){
//		a=aa;b=bb;c=cc;
//	}
//	NoD(long m,long l,long r,long t){
//		ms=m;ls=l;rs=r;ts=t;
//	}
	@Override
	public boolean equals(Object o) {
		if(o!=null && o.getClass()==getClass()) {
			NoD c= (NoD) o;
			return c.a==a && c.b==b;
		}
		return false;
	}
	@Override
	public int hashCode() {
		return s.hashCode();
	}
}
class DisJoint {
	int[] arr;
	int[] parent;
	int[] rank;
	DisJoint(int n){
		arr=new int[n+1];
		parent=new int[n+1];
		rank=new int[n+1];
		for(int i=1;i<=n;i++) {
			arr[i]=i;
			parent[i]=i;
			rank[i]=0;
		}
	}

	int find(int value) {
		int par=parent[value];
		if(par==value)
			return par;
		parent[value]=find(par);
		return parent[value];
	}
	
	void union(int data1,int data2) {
		int parent1=find(data1);
		int parent2=find(data2);
		if(parent1!=parent2) {
			if(rank[parent1]>=rank[parent2]) {
				parent[parent2]=parent1;
				if(rank[parent1]==rank[parent2])
					rank[parent1]++;
			}
			else {
				parent[parent1]=parent2;
			}
		}
		
	}
	

}

class Seg{
	long[] st;
	long[] arr;
	long[] lazy;
	Seg(int n){
		st=new long[4*n];
		//lazy=new long[4*n];
		
	}
	void build(int index,int low,int high) {
		if(low==high) {
			st[index]=arr[low];
		}
		else {
			int middle=(low+high)/2;
			build(2*index+1,low,middle);
			build(2*index+2,middle+1,high);
			st[index]=Math.min(st[2*index+1], st[2*index+2]);
		}
	}
	
	long query(int index,int low,int high, int ql,int qh) {
//		if(lazy[index]!=0) {
//			st[index]+=lazy[index];
//			if(low<high) {
//				lazy[2*index+1]+=lazy[index];
//				lazy[2*index+2]+=lazy[index];
//				
//			}
//			lazy[index]=0;
//		}
		
		if(ql<=low && high<=qh) {
			return st[index];
		}
		else if(!(ql>high || qh<low)) {
			int middle=(low+high)/2;
			long left=query(2*index+1,low,middle,ql,qh);
			long right=query(2*index+2,middle+1,high,ql,qh);
			//st[index]=Math.max(st[2*index+1], st[2*index+2]);
			return Math.max(left,right);
			
		}
		return 0;
	}
	
	
	void u1(int index, int low,int high, int pos,long v) {
//		if(lazy[index]!=0) {
//			st[index]+=lazy[index];
//			if(low<high) {
//				lazy[2*index+1]+=lazy[index];
//				lazy[2*index+2]+=lazy[index];
//				
//			}
//			lazy[index]=0;
//		}
		if(low==high) {
			st[index]=v;
		}
		else {
			int middle=(low+high)/2;
			if(pos<=middle) u1(2*index+1,low,middle,pos,v);
			else u1(2*index+2,middle+1,high,pos,v);
			st[index]=Math.max(st[2*index+1],st[2*index+2]);
		}
	}
	
	
}
class Reader {
    static BufferedReader reader;
    static StringTokenizer tokenizer;
    /** call this method to initialize reader for InputStream */
    static void init(InputStream input) {
        reader = new BufferedReader(
                     new InputStreamReader(input) );
        tokenizer = new StringTokenizer("");
    }
    /** get next word */
    static String nextLine() throws IOException{
    	return reader.readLine();
    }
    static String next() throws IOException {
        while ( ! tokenizer.hasMoreTokens() ) {
            //TODO add check for eof if necessary
            tokenizer = new StringTokenizer(
                   reader.readLine() );
        }
        return tokenizer.nextToken();
    }
    static int nextInt() throws IOException {
        return Integer.parseInt( next() );
    }
    static long nextLong() throws IOException {
        return Long.parseLong( next() );
    }
    static double nextDouble() throws IOException {
        return Double.parseDouble( next() );
    }
}