You are given a sequence of n pairs of integers: (a_1, b_1), (a_2, b_2), ... , (a_n, b_n). This sequence is called bad if it is sorted in non-descending order by first elements or if it is sorted in non-descending order by second elements. Otherwise the sequence is good. There are examples of good and bad sequences:

  * s = [(1, 2), (3, 2), (3, 1)] is bad because the sequence of first elements is sorted: [1, 3, 3]; 
  * s = [(1, 2), (3, 2), (1, 2)] is bad because the sequence of second elements is sorted: [2, 2, 2]; 
  * s = [(1, 1), (2, 2), (3, 3)] is bad because both sequences (the sequence of first elements and the sequence of second elements) are sorted; 
  * s = [(1, 3), (3, 3), (2, 2)] is good because neither the sequence of first elements ([1, 3, 2]) nor the sequence of second elements ([3, 3, 2]) is sorted. 



Calculate the number of permutations of size n such that after applying this permutation to the sequence s it turns into a good sequence. 

A permutation p of size n is a sequence p_1, p_2, ... , p_n consisting of n distinct integers from 1 to n (1 ≤ p_i ≤ n). If you apply permutation p_1, p_2, ... , p_n to the sequence s_1, s_2, ... , s_n you get the sequence s_{p_1}, s_{p_2}, ... , s_{p_n}. For example, if s = [(1, 2), (1, 3), (2, 3)] and p = [2, 3, 1] then s turns into [(1, 3), (2, 3), (1, 2)].

Input

The first line contains one integer n (1 ≤ n ≤ 3 ⋅ 10^5).

The next n lines contains description of sequence s. The i-th line contains two integers a_i and b_i (1 ≤ a_i, b_i ≤ n) — the first and second elements of i-th pair in the sequence.

The sequence s may contain equal elements.

Output

Print the number of permutations of size n such that after applying this permutation to the sequence s it turns into a good sequence. Print the answer modulo 998244353 (a prime number).

Examples

Input


3
1 1
2 2
3 1


Output


3


Input


4
2 3
2 2
2 1
2 4


Output


0


Input


3
1 1
1 1
2 3


Output


4

Note

In first test case there are six permutations of size 3: 

  1. if p = [1, 2, 3], then s = [(1, 1), (2, 2), (3, 1)] — bad sequence (sorted by first elements); 
  2. if p = [1, 3, 2], then s = [(1, 1), (3, 1), (2, 2)] — bad sequence (sorted by second elements); 
  3. if p = [2, 1, 3], then s = [(2, 2), (1, 1), (3, 1)] — good sequence; 
  4. if p = [2, 3, 1], then s = [(2, 2), (3, 1), (1, 1)] — good sequence; 
  5. if p = [3, 1, 2], then s = [(3, 1), (1, 1), (2, 2)] — bad sequence (sorted by second elements); 
  6. if p = [3, 2, 1], then s = [(3, 1), (2, 2), (1, 1)] — good sequence. 
from sys import stdin


def fast2():
    import os, sys, atexit
    from cStringIO import StringIO as BytesIO
    # range = xrange
    sys.stdout = BytesIO()
    atexit.register(lambda: os.write(1, sys.stdout.getvalue()))
    return BytesIO(os.read(0, os.fstat(0).st_size)).readline


def fact(be, en):
    res = [1]
    for i in range(be, en + 1):
        res.append(mult(res[-1], i))
    return res


# input = fast2()
get_col = lambda arr, i: [row[i] for row in arr]
rints = lambda: [int(x) for x in stdin.readline().split()]
add = lambda a, b: (a + b) % mod
mult = lambda a, b: (a * b) % mod
mod, ans = 998244353, 0

n = int(input())
a = sorted([tuple(rints()) for _ in range(n)])
mem = [[0, 0] for _ in range(n + 1)]
facs = fact(1, n)

for i, j in a:
    mem[i][0] += 1
    mem[j][1] += 1

cur = [1, 1, 0]
for i, j in mem:
    cur[0] = mult(cur[0], facs[i])
    cur[1] = mult(cur[1], facs[j])

if sorted(get_col(a, 1)) == get_col(a, 1):
    cur[-1], c = 1, 1
    for i in range(1, n):
        if a[i] != a[i - 1]:
            cur[-1] = mult(cur[-1], facs[c])
            c = 0
        c += 1
    cur[-1] = mult(cur[-1], facs[c])

ans = add(add(facs[n], -add(cur[0], cur[1])), cur[-1])
print(ans)
