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 PYTHON):

Solution:
import atexit
import io
import sys

buff = io.BytesIO()
sys.stdout = buff


@atexit.register
def write():
    sys.__stdout__.write(buff.getvalue())


def bs(a,low,high,arr,t):
	if t == 0:
		ans = -1
	else:
		ans = len(arr)
	while low <= high:
		mid = (high+low)/2
		if arr[mid][0] < a:
			if not t:
				ans = mid
			low = mid+1
		else:
			if t:
				ans = mid
			high = mid-1
	return ans

n = input()
greater = []
lesser = []
ans1 = []
ans2 = []
for i in xrange(n):
	a,b = map(int, raw_input().split())
	if a > b:
		greater.append((a,i))
	else:
		lesser.append((b,i))
i = len(lesser)-1
lesser.sort()
greater.sort()
while i >= 0:
	ans1.append(lesser[i][1])
	i = bs(lesser[i][0], 0, i-1, lesser, 0)

i = 0
while i < len(greater):
	ans2.append(greater[i][1])
	i = bs(greater[i][0], i+1, len(greater)-1, greater, 1)
if len(ans1) >= len(ans2):
	print len(ans1)
	for a in ans1:
		print a+1,

else:
	print len(ans2)
	for a in ans2:
		print a+1,