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. 
import java.util.Arrays;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.Queue;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.StringTokenizer;
import java.util.Random;
import java.io.PrintWriter;
/*
    Solution Created: 13:36:37 28/08/2019
    Custom Competitive programming helper.
*/

public class Main {
	public static long MOD = 998244353;
	public static void solve(Reader in, Writer out) {
		int n = in.nextInt();
		long[] fact = new long[n+1];
		fact[0] = 1;
		for(int i = 1; i<=n; i++) fact[i] = (fact[i-1]*i)%MOD;
		Pair[] a = new Pair[n];
		for(int i = 0; i<n; i++) a[i] = new Pair(in.nextInt(), in.nextInt());
		Arrays.sort(a);
		int[] fa = new int[n+1];
		int[] fb = new int[n+1];
		for(int i = 0; i<n; i++) {
			fa[a[i].x]++;
			fb[a[i].y]++;
		}
		long cnt1 = 1, cnt2 = 1;
		for(int i = 0; i<=n; i++) {
			cnt1 = Util.modMul(cnt1, fact[fa[i]], MOD);
			cnt2 = Util.modMul(cnt2, fact[fb[i]], MOD);
		}
		boolean is = true;
		for(int i = 1; i<n&&is; i++) if(a[i-1].y>a[i].y) is = false;
		long rem = 0;
		if(is) {
			rem = 1;
			int cnt = 1;
			for(int i = 1; i<n; i++) {
				if(a[i-1].x == a[i].x && a[i-1].y == a[i].y) cnt++;
				else cnt = 1;
				rem = Util.modMul(rem, cnt, MOD);
			}
		}
		long ans = fact[n];
		ans = Util.modAdd(ans, MOD-cnt1, MOD);
		ans = Util.modAdd(ans, MOD-cnt2, MOD);
		ans = Util.modAdd(ans, rem, MOD);
		out.println(ans);
	}
	static class Pair implements Comparable<Pair>{
		int x, y;
		public Pair(int x, int y) {
			this.x = x;
			this.y = y;
		}
		@Override
		public int compareTo(Pair o) {
			if(this.x == o.x) return this.y - o.y;
			return this.x - o.x;
		}
	}
	public static void main(String[] args) {
		Reader in = new Reader();
		Writer out = new Writer();
		solve(in, out);
		out.exit();
	}

static class Graph {
	private ArrayList<Integer> con[];
	private boolean[] visited;

	public Graph(int n) {
		con = new ArrayList[n];
		for (int i = 0; i < n; ++i)
			con[i] = new ArrayList();
		visited = new boolean[n];
	}

	public void reset() {
		Arrays.fill(visited, false);
	}

	public void addEdge(int v, int w) {
		con[v].add(w);
	}

	public void dfs(int cur) {
		visited[cur] = true;
		for (Integer v : con[cur]) {
			if (!visited[v]) {
				dfs(v);
			}
		}
	}

	public void bfs(int cur) {
		Queue<Integer> q = new LinkedList<>();
		q.add(cur);
		visited[cur] = true;
		while (!q.isEmpty()) {
			cur = q.poll();
			for (Integer v : con[cur]) {
				if (!visited[v]) {
					visited[v] = true;
					q.add(v);
				}
			}
		}
	}
}

static class Reader {
	static BufferedReader br;
	static StringTokenizer st;
	private int charIdx = 0;
	private String s;

	public Reader() {
		this.br = new BufferedReader(new InputStreamReader(System.in));
	}

	public int[] na(int n) {
		int[] a = new int[n];
		for (int i = 0; i < n; i++)
			a[i] = nextInt();
		return a;
	}

	public double[] nd(int n) {
		double[] a = new double[n];
		for (int i = 0; i < n; i++)
			a[i] = nextDouble();
		return a;
	}

	public char nextChar() {
		if (s == null || charIdx >= s.length()) {
			if (st == null || !st.hasMoreTokens())
				try {
					readLine();
				} catch (Exception e) {
				}
			s = st.nextToken();
			charIdx = 0;
		}
		return s.charAt(charIdx++);
	}

	public long[] nl(int n) {
		long[] a = new long[n];
		for (int i = 0; i < n; i++)
			a[i] = nextLong();
		return a;
	}

	public char[] nca() {
		return next().toCharArray();
	}

	public String[] nS(int n) {
		String[] a = new String[n];
		for (int i = 0; i < n; i++)
			a[i] = next();
		return a;
	}

	public int nextInt() {
		if (st == null || !st.hasMoreTokens())
			try {
				readLine();
			} catch (Exception e) {
			}
		return Integer.parseInt(st.nextToken());
	}

	public double nextDouble() {
		if (st == null || !st.hasMoreTokens())
			try {
				readLine();
			} catch (Exception e) {
			}
		return Double.parseDouble(st.nextToken());
	}

	public Long nextLong() {
		if (st == null || !st.hasMoreTokens())
			try {
				readLine();
			} catch (Exception e) {
			}
		return Long.parseLong(st.nextToken());
	}

	public String next() {
		if (st == null || !st.hasMoreTokens())
			try {
				readLine();
			} catch (Exception e) {
			}
		return st.nextToken();
	}

	public static void readLine() {
		try {
			st = new StringTokenizer(br.readLine());
		} catch (Exception e) {
		}
	}
}

static class Sort {
	static Random random = new Random();
	public static void sortArray(int[] s) {
        shuffle(s);
        Arrays.sort(s);
    }
	public static void sortArray(long[] s) {
        shuffle(s);
        Arrays.sort(s);
    }
	public static void sortArray(String[] s) {
        shuffle(s);
        Arrays.sort(s);
    }
	public static void sortArray(char[] s) {
        shuffle(s);
        Arrays.sort(s);
    }
    private static void shuffle(int[] s) {
        for (int i = 0; i < s.length; ++i) {
            int j = random.nextInt(i + 1);
            int t = s[i];
            s[i] = s[j];
            s[j] = t;
        }
    }
    private static void shuffle(long[] s) {
        for (int i = 0; i < s.length; ++i) {
            int j = random.nextInt(i + 1);
            long t = s[i];
            s[i] = s[j];
            s[j] = t;
        }
    }
    private static void shuffle(String[] s) {
        for (int i = 0; i < s.length; ++i) {
            int j = random.nextInt(i + 1);
            String t = s[i];
            s[i] = s[j];
            s[j] = t;
        }
    }
    private static void shuffle(char[] s) {
        for (int i = 0; i < s.length; ++i) {
            int j = random.nextInt(i + 1);
            char t = s[i];
            s[i] = s[j];
            s[j] = t;
        }
    }
}

static class Util{
	    static boolean isPrime(int n) { 
	        if (n <= 1) return false; 
	        if (n <= 3) return true; 
	        if (n % 2 == 0 || n % 3 == 0) return false; 
	        for (int i = 5; i * i <= n; i = i + 6) 
	            if (n % i == 0 || n % (i + 2) == 0) 
	            return false; 
	        return true; 
	    }
		public static int upperBound(long[] a, long v) {
			int l=0, h=a.length-1, ans = -1;
			while(l<h) {
				int mid = (l+h)/2;
				if(a[mid]<=v) {
					ans = mid;
					l = mid+1;
				}else h = mid-1;
			}
			return ans;
		}
		public static int lowerBound(long[] a, long v) {
			int l=0, h=a.length-1, ans = -1;
			while(l<h) {
				int mid = (l+h)/2;
				if(v<=a[mid]) {
					ans = mid;
					h = mid-1;
				}else l = mid-1;
			}
			return ans;
		}
	    public static boolean[] getSieve(int n) {
	        boolean[] isPrime = new boolean[n+1];
	        for (int i = 2; i <= n; i++) isPrime[i] = true;
	        for (int i = 2; i*i <= n; i++) if (isPrime[i]) 
	                for (int j = i; i*j <= n; j++) isPrime[i*j] = false;
	        return isPrime;
	    }
	    public static int gcd(int a, int b) { 
	        if (a == 0) 
	            return b; 
	        return gcd(b%a, a); 
	    }
		public static long modAdd(long a, long b, long mod) {
			return (a%mod+b%mod)%mod;
		}
		public static long modMul(long a, long b, long mod) {
			return ((a%mod)*(b%mod))%mod;
		}
		public static void dbg(Object... o) { 
			System.out.println(Arrays.deepToString(o)); 
		}
	}

static class Writer {
	private PrintWriter pw;
	public Writer(){
		pw = new PrintWriter(System.out);
	}
	
	public void printArray(int[] a) {
		for(int i = 0; i<a.length; i++) print(a[i]+" ");
	}
	public void printlnArray(int[] a) {
		for(int i = 0; i<a.length; i++) print(a[i]+" ");
		pw.println();
	}
	public void printArray(long[] a) {
		for(int i = 0; i<a.length; i++) print(a[i]+" ");
	}
	public void printlnArray(long[] a) {
		for(int i = 0; i<a.length; i++) print(a[i]+" ");
		pw.println();
	}
	public void print(Object o) {
		pw.print(o.toString());
	}
	public void println(Object o) {
		pw.println(o.toString());
	}
	public void println() {
		pw.println();
	}
	public void flush() {
		pw.flush();
	}
	public void exit() {
		pw.close();
	}
}
}
