Problem: During the research on properties of the greatest common divisor (GCD) of a set of numbers, Ildar, a famous mathematician, introduced a brand new concept of the weakened common divisor (WCD) of a list of pairs of integers.

For a given list of pairs of integers (a_1, b_1), (a_2, b_2), ..., (a_n, b_n) their WCD is arbitrary integer greater than 1, such that it divides at least one element in each pair. WCD may not exist for some lists.

For example, if the list looks like [(12, 15), (25, 18), (10, 24)], then their WCD can be equal to 2, 3, 5 or 6 (each of these numbers is strictly greater than 1 and divides at least one number in each pair).

You're currently pursuing your PhD degree under Ildar's mentorship, and that's why this problem was delegated to you. Your task is to calculate WCD efficiently.

Input

The first line contains a single integer n (1 ≤ n ≤ 150 000) — the number of pairs.

Each of the next n lines contains two integer values a_i, b_i (2 ≤ a_i, b_i ≤ 2 ⋅ 10^9).

Output

Print a single integer — the WCD of the set of pairs. 

If there are multiple possible answers, output any; if there is no answer, print -1.

Examples

Input

3
17 18
15 24
12 15


Output

6

Input

2
10 16
7 17


Output

-1


Input

5
90 108
45 105
75 40
165 175
33 30


Output

5

Note

In the first example the answer is 6 since it divides 18 from the first pair, 24 from the second and 12 from the third ones. Note that other valid answers will also be accepted.

In the second example there are no integers greater than 1 satisfying the conditions.

In the third example one of the possible answers is 5. Note that, for example, 15 is also allowed, but it's not necessary to maximize the output.

Solution (in JAVA):

Solution:
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.math.BigInteger;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.Random;
import java.util.Stack;
import java.util.StringTokenizer;
import java.util.TreeMap;
import java.util.TreeSet;

// CFPS -> CodeForcesProblemSet
public final class CFPS {
	static FastReader fr = new FastReader();
	static PrintWriter out = new PrintWriter(System.out);
	static final int gigamod = 1000000007;
	static int t = 1;
	static double epsilon = 0.00000001;
	
	public static void main(String[] args) {
		OUTER: 
		for (int tc = 0; tc < t; tc++) {
			
			int n = fr.nextInt();
			
			// Observations: 
			
			// 1. If the answer exists, it will be a number among
			// the prime factors of: 
			// 		a. 1st of pair 1
			// 		b. 2nd of pair 1
			
			// We can try for every prime factor and check if it
			// happens for any.
			
			long[][] ab = new long[n][2];
			for (int i = 0; i < n; i++)
				ab[i] = fr.nextLongArray(2);
			
			ArrayList<Long> possPrimes = new ArrayList<>();
			
			TreeMap<Long, Integer> fnp1 = primeFactorization(ab[0][0]);
			TreeMap<Long, Integer> fnp2 = primeFactorization(ab[0][1]);
			
			for (long factor : fnp1.keySet())
				possPrimes.add(factor);
			
			for (long factor : fnp2.keySet())
				possPrimes.add(factor);
			
			// We will check for every possible factor, if it goes
			// through everything.
			
			for (long factor : possPrimes) {
				// Checking if factor passes through.
				boolean passes = true;
				for (int i = 1; i < n; i++) {
					if (ab[i][0] % factor != 0 && ab[i][1] % factor != 0) {
						passes = false;
						break;
					}
				}
				
				if (passes) {
					out.println(factor);
					continue OUTER;
				}
			}
			
			out.println(-1);
		}
		out.close();
	}
	
	static String reverse(String s) {
		
		StringBuilder sb = new StringBuilder();
		int n = s.length();
		
		for (int i = n - 1; i > -1; i--) {
			sb.append(s.charAt(i));
		}
		
		return sb.toString();
	}
	
	static long power(long x, int y)
	  {
		// int p = 998244353;
		// int p = gigamod;
	    long res = 1; // Initialize result
	 
	    x = x/* % p*/; // Update x if it is more than or
	    // equal to p
	 
	    if (x == 0)
	      return 0; // In case x is divisible by p;
	 
	    while (y > 0)
	    {
	 
	      // If y is odd, multiply x with result
	      if ((y & 1) != 0)
	        res = (res * x)/* % p*/;
	 
	      // y must be even now
	      y = y >> 1; // y = y/2
	      x = (x * x)/* % p*/;
	    }
	    return res;
	  }
	
	// Maps elements in a 2D matrix serially to elements in 
	// a 1D array.
	static int mapTo1D(int row, int col, int n, int m) {
		return row * m + col;
	}
	
	// Inverse of what the one above does.
	static int[] mapTo2D(int idx, int n, int m) {
		int[] rnc = new int[2];
		rnc[0] = idx / m;
		rnc[1] = idx % m;
		return rnc;
	}
	
	// Checks if s has subsequence t.
	static boolean hasSubsequence(String s, String t) {
		char[] schars = s.toCharArray();
		char[] tchars = t.toCharArray();
		int slen = schars.length, tlen = tchars.length;
		int tctr = 0;
		
		if (slen < tlen) return false;
		
		for (int i = 0; i < slen || i < tlen; i++) {
			if (tctr == tlen) break;
			if (schars[i] == tchars[tctr]) {
				tctr++;
			}
		}
		
		if (tctr == tlen) return true;
		return false;
	}
	
	// Returns the binary string of length at least bits.
	static String toBinaryString(long num, int bits) {
		StringBuilder sb = new StringBuilder(Long.toBinaryString(num));
		sb.reverse();
		for (int i = sb.length(); i < bits; i++)
			sb.append('0');
		return sb.reverse().toString();
	}
	
	static class CountMap extends TreeMap<Long, Integer>{
		
		CountMap() {
		}
		
		CountMap(CountMap cm) {
			
		}
		
		public void removeTM(Long key) {
			super.remove(key);
		}
		
		public void removeTM(Integer key) {
			super.remove((long) key);
		}
		
		public Integer put(Long key) {
			if (super.containsKey(key)) {
				return super.put(key, super.get(key) + 1);
			} else {
				return super.put(key, 1);
			}
		}
		
		public Integer put(int key) {
			if (super.containsKey((long) key)) {
				return super.put((long) key, super.get((long) key) + 1);
			} else {
				return super.put((long) key, 1);
			}
		}
		
		public Integer remove(Long key) {
			Integer count = super.get(key);
			if (count == null) return -1;
			if (count == 1)
				return super.remove(key);
			else
				return super.put(key, super.get(key) - 1);
		}
		
		public Integer remove(int key) {
			Integer count = super.get((long) key);
			if (count == null) return -1;
			if (count == 1)
				return super.remove((long) key);
			else
				return super.put((long) key, super.get((long) key) - 1);
		}
		
		public Integer get(int key) {
			Integer count = super.get((long) key);
			if (count == null)
				return 0;
			return count;
		}
		
		public Integer get(long key) {
			Integer count = super.get(key);
			if (count == null)
				return 0;
			return count;
		}
	}
	
	static class Point implements Comparable<Point> {
		long x;
		long y;
		int id;
		
		Point() {
			x = y = id = 0;
		}
		
		Point(Point p) {
			this.x = p.x;
			this.y = p.y;
			this.id = p.id;
		}
		
		Point(long a, long b, int id) {
			this.x = a;
			this.y = b;
			this.id = id;
		}
		
		Point(long a, long b) {
			this.x = a;
			this.y = b;
		}
		
		@Override
		public int compareTo(Point o) {
			if (this.x > o.x)
				return 1;
			if (this.x < o.x)
				return -1;
			if (this.y > o.y)
				return 1;
			if (this.y < o.y)
				return -1;
			return 0;
		}
		
		public boolean equals(Point that) {
			return this.compareTo(that) == 0;
		}
	}
	
	static class PointComparator implements Comparator<Point> {
		@Override
		public int compare(Point o1, Point o2) {
			
			// Comparision has to be done by (a-b).
			
			long amb1 = o1.x - o1.y;
			long amb2 = o2.x - o2.y;
			
			// Order has to be reverse.
			if (amb1 > amb2) 
				return -1;
			
			if (amb2 > amb1)
				return 1;
			
			return 0;
		}
	}
	
	// Returns the largest power of k that fits into n.
	static int largestFittingPower(long n, long k) {
		int lo = 0, hi = logk(Long.MAX_VALUE, 3);
		int largestPower = -1;
		while (lo <= hi) {
			int mid = lo + (hi - lo)/2;
			
			long val = (long) Math.pow(k, mid);
			if (val <= n) {
				largestPower = mid;
				lo = mid + 1;
			} else {
				hi = mid - 1;
			}
		}
		return largestPower;
	}
	
	static String bitSetToString(int set) {
		// We have to print all the elements that are present
		// in the set.
		StringBuilder sb = new StringBuilder();
		for (int i = 0; i < 30; i++) {
			if (((set >> i) & 1) == 1) {
				// The 'i'th bit is on meaning that the element 'i' is 
				// present in the set.
				sb.append((i + 1) + " ");
			}
		}
		sb.append("\n");
		return sb.toString();
	}
	
	static String displayBitSet(long set) {
		// We have to print all the elements that are present
		// in the set.
		StringBuilder sb = new StringBuilder();
		for (int i = 0; i < 60; i++) {
			if (((set >> i) & 1) == 1) {
				// The 'i'th bit is on meaning that the element 'i' is 
				// present in the set.
				sb.append((i + 1) + " ");
			}
		}
		sb.append("\n");
		return sb.toString();
	}
	
	static int addToBitSet(int set, int element) {
		set = (set) | (1 << (element - 1));
		return set;
	}
	
	static int removeFromBitSet(int set, int element) {
		// Checking whether the bit is present.
		if ((set & (1 << (element - 1))) == 0) return set;
		set = set ^ (1 << (element - 1));
		return set;
	}
	
	// Returns map of factor and its power in the number.
	static TreeMap<Long, Integer> primeFactorization(long num) {
		TreeMap<Long, Integer> map = new TreeMap<>();
		while (num % 2 == 0) {
			num /= 2;
			Integer pwrCnt = map.get(2L);
			map.put(2L, pwrCnt != null ? pwrCnt + 1 : 1);
		}
		
		for (long i = 3; i * i <= num; i += 2) {
			while (num % i == 0) {
				num /= i;
				Integer pwrCnt = map.get(i);
				map.put(i, pwrCnt != null ? pwrCnt + 1 : 1);
			}
		}
		
		// If the number is prime, we have to add it to the 
		// map.
		if (num != 1)
			map.put(num, 1);
		
		return map;
	}
	
	// Returns map of factor and its power in the number.
	static TreeMap<Integer, Integer> primeFactorization(int num) {
		TreeMap<Integer, Integer> map = new TreeMap<>();
		while (num % 2 == 0) {
			num /= 2;
			Integer pwrCnt = map.get(2);
			map.put(2, pwrCnt != null ? pwrCnt + 1 : 1);
		}
		
		for (int i = 3; i * i <= num; i += 2) {
			while (num % i == 0) {
				num /= i;
				Integer pwrCnt = map.get(i);
				map.put(i, pwrCnt != null ? pwrCnt + 1 : 1);
			}
		}
		
		// If the number is prime, we have to add it to the 
		// map.
		if (num != 1)
			map.put(num, 1);
		
		return map;
	}
	
	static TreeSet<Long> divisors(long num) {
		TreeSet<Long> divisors = new TreeSet<Long>();
		divisors.add(1L);
		divisors.add(num);
		
		for (long i = 2; i * i <= num; i++) {
			if (num % i == 0) {
				divisors.add(num/i);
				divisors.add(i);
			}
		}
		return divisors;
	}
	
	static void dfs(int node, boolean[] marked, ArrayList<Integer>[] adj) {
		if (marked[node]) return;

		marked[node] = true;
		for (int adjc : adj[node])
			dfs(adjc, marked, adj);
	}
	
	// Returns the index of the first element
	// larger than or equal to val.
	static int bsearch(int[] arr, int val, int lo, int hi) {
		int idx = -1;
		while (lo <= hi) {
			int mid = lo + (hi - lo)/2;
			if (arr[mid] >= val) {
				idx = mid;
				hi = mid - 1;
			} else
				lo = mid + 1;
		}
		return idx;
	}
	
	static int bsearch(long[] arr, long val, int lo, int hi) {
		int idx = -1;
		while (lo <= hi) {
			int mid = lo + (hi - lo)/2;
			if (arr[mid] >= val) {
				idx = mid;
				hi = mid - 1;
			} else
				lo = mid + 1;
		}
		return idx;
	}
	
	// Returns the index of the last element 
	// smaller than or equal to val.
	static int bsearch(long[] arr, long val, int lo, int hi, boolean sMode) {
		int idx = -1;
		while (lo <= hi) {
			int mid = lo + (hi - lo)/2;
			if (arr[mid] > val) {
				hi = mid - 1;
			} else {
				idx = mid;
				lo = mid + 1;
			}
		}
		return idx;
	}
	
	static int bsearch(int[] arr, long val, int lo, int hi, boolean sMode) {
		int idx = -1;
		while (lo <= hi) {
			int mid = lo + (hi - lo)/2;
			if (arr[mid] > val) {
				hi = mid - 1;
			} else {
				idx = mid;
				lo = mid + 1;
			}
		}
		return idx;
	}
	
	static long factorial(long n) {
		if (n <= 1)
			return 1;
		long factorial = 1;
		for (int i = 1; i <= n; i++)
			factorial = mod(factorial * i);
		return factorial;
	}
	
	static long factorialInDivision(long a, long b) {
		if (a == b)
			return 1;
		if (b < a) {
			long temp = a;
			a = b;
			b = temp;
		}
		
		long factorial = 1;
		for (long i = a + 1; i <= b; i++)
			factorial = mod(factorial * i);
		return factorial;
	}
	
	static BigInteger factorialInDivision(BigInteger a, BigInteger b) {
		if (a.equals(b))
			return BigInteger.ONE;
		return a.multiply(factorialInDivision(a.subtract(BigInteger.ONE), b));
	}
	
	static long nCr(long n, long r) {
		long p = gigamod;
	    // Base case
	    if (r == 0)
	        return 1;
	 
	    // Fill factorial array so that we
	    // can find all factorial of r, n
	    // and n-r
	    long fac[] = new long[(int)n + 1];
	    fac[0] = 1;
	    for (int i = 1; i <= n; i++)
	        fac[i] = fac[i - 1] * i % p;
	 
	    return (fac[(int)n] * modInverse(fac[(int)r], p) % p
	                    * modInverse(fac[(int)n - (int)r], p) % p) % p;
	}
	
	static long modInverse(long n, long p) {
	    return power(n, p - 2, p);
	}
	
	static long power(long x, long y, long p) {
	    long res = 1; // Initialize result
	 
	    x = x % p; // Update x if it is more than or
	    // equal to p
	 
	    while (y > 0) {
	        // If y is odd, multiply x with result
	        if ((y & 1)==1)
	            res = (res * x) % p;
	 
	        // y must be even now
	        y = y >> 1; // y = y/2
	        x = (x * x) % p;
	    }
	    return res;
	}
	
	static long nPr(long n, long r) {
		return factorialInDivision(n, n - r);
	}
	
	static int log2(long n) {
		return (int)(Math.log(n) / Math.log(2));
	}
	
	static double log2(long n, boolean doubleMode) {
		return (Math.log(n) / Math.log(2));
	}
	
	static int logk(long n, long k) {
		return (int)(Math.log(n) / Math.log(k));
	}
	
	// Sieve of Eratosthenes: 
	static boolean[] primeGenerator(int upto) {
		boolean[] isPrime = new boolean[upto + 1];
		Arrays.fill(isPrime, true);
		isPrime[1] = isPrime[0] = false;

		for (long i = 2; i * i < upto + 1; i++)
			if (isPrime[(int) i])
				// Mark all the multiples greater than or equal
				// to the square of i to be false.
				for (long j = i; j * i < upto + 1; j++)
					isPrime[(int) j * (int) i] = false;
		return isPrime;
	}

	static int gcd(int a, int b) {
		if (b == 0) {
			return a;
		} else {
			return gcd(b, a % b);
		}
	}
	
	static long gcd(long a, long b) {
		if (b == 0) {
			return a;
		} else {
			return gcd(b, a % b);
		}
	}
	
	static int gcd(int[] arr) {
		int n = arr.length;
		int gcd = arr[0];
		for (int i = 1; i < n; i++) {
			gcd = gcd(gcd, arr[i]);
		}
		return gcd;
	}
	
	static long gcd(long[] arr) {
		int n = arr.length;
		long gcd = arr[0];
		for (int i = 1; i < n; i++) {
			gcd = gcd(gcd, arr[i]);
		}
		return gcd;
	}
	
	static long lcm(int[] arr) {
		long lcm = arr[0];
		int n = arr.length;
		for (int i = 1; i < n; i++) {
			lcm = (lcm * arr[i]) / gcd(lcm, arr[i]);
		}
		return lcm;
	}
	
	static long lcm(long[] arr) {
		long lcm = arr[0];
		int n = arr.length;
		for (int i = 1; i < n; i++) {
			lcm = (lcm * arr[i]) / gcd(lcm, arr[i]);
		}
		return lcm;
	}
	
	static long lcm(int a, int b) {
		return (a * b)/gcd(a, b);
	}
	
	static long lcm(long a, long b) {
		return (a * b)/gcd(a, b);
	}
	
	static boolean less(int a, int b) {
		return a < b ? true : false;
	}
	
	static boolean isSorted(int[] a) {
		for (int i = 1; i < a.length; i++) {
			if (less(a[i], a[i - 1]))
				return false;
		}
		return true;
	}
	
	static boolean isSorted(long[] a) {
		for (int i = 1; i < a.length; i++) {
			if (a[i] < a[i - 1])
				return false;
		}
		return true;
	}

	static void swap(int[] a, int i, int j) {
		int temp = a[i];
		a[i] = a[j];
		a[j] = temp;
	}
	
	static void swap(long[] a, int i, int j) {
		long temp = a[i];
		a[i] = a[j];
		a[j] = temp;
	}
	
	static void swap(double[] a, int i, int j) {
		double temp = a[i];
		a[i] = a[j];
		a[j] = temp;
	}
	
	static void swap(char[] a, int i, int j) {
		char temp = a[i];
		a[i] = a[j];
		a[j] = temp;
	}
	
	static void sort(int[] arr) {
		shuffleArray(arr, 0, arr.length - 1);
		Arrays.sort(arr);
	}
	
	static void sort(char[] arr) {
		shuffleArray(arr, 0, arr.length - 1);
		Arrays.sort(arr);
	}
	
	static void sort(long[] arr) {
		shuffleArray(arr, 0, arr.length - 1);
		Arrays.sort(arr);
	}
	
	static void sort(double[] arr) {
		shuffleArray(arr, 0, arr.length - 1);
		Arrays.sort(arr);
	}
	
	static void reverseSort(int[] arr) {
		shuffleArray(arr, 0, arr.length - 1);
		Arrays.sort(arr);
		int n = arr.length;
		for (int i = 0; i < n/2; i++)
			swap(arr, i, n - 1 - i);
	}
	
	static void reverseSort(char[] arr) {
		shuffleArray(arr, 0, arr.length - 1);
		Arrays.sort(arr);
		int n = arr.length;
		for (int i = 0; i < n/2; i++)
			swap(arr, i, n - 1 - i);
	}
	
	static void reverseSort(long[] arr) {
		shuffleArray(arr, 0, arr.length - 1);
		Arrays.sort(arr);
		int n = arr.length;
		for (int i = 0; i < n/2; i++)
			swap(arr, i, n - 1 - i);
	}
	
	static void reverseSort(double[] arr) {
		shuffleArray(arr, 0, arr.length - 1);
		Arrays.sort(arr);
		int n = arr.length;
		for (int i = 0; i < n/2; i++)
			swap(arr, i, n - 1 - i);
	}
	
	static void shuffleArray(long[] arr, int startPos, int endPos) {
		Random rnd = new Random();
		for (int i = startPos; i < endPos; ++i) {
			long tmp = arr[i];
			int randomPos = i + rnd.nextInt(endPos - i);
			arr[i] = arr[randomPos];
			arr[randomPos] = tmp;
		}
	}
	
	static void shuffleArray(int[] arr, int startPos, int endPos) {
		Random rnd = new Random();
		for (int i = startPos; i < endPos; ++i) {
			int tmp = arr[i];
			int randomPos = i + rnd.nextInt(endPos - i);
			arr[i] = arr[randomPos];
			arr[randomPos] = tmp;
		}
	}
	
	static void shuffleArray(double[] arr, int startPos, int endPos) {
		Random rnd = new Random();
		for (int i = startPos; i < endPos; ++i) {
			double tmp = arr[i];
			int randomPos = i + rnd.nextInt(endPos - i);
			arr[i] = arr[randomPos];
			arr[randomPos] = tmp;
		}
	}
	
	private static void shuffleArray(char[] arr, int startPos, int endPos) {
		Random rnd = new Random();
		for (int i = startPos; i < endPos; ++i) {
			char tmp = arr[i];
			int randomPos = i + rnd.nextInt(endPos - i);
			arr[i] = arr[randomPos];
			arr[randomPos] = tmp;
		}
	}
	
	static boolean isPrime(long n) {
		if (n <= 1)
			return false;
		if (n <= 3)
			return true;

		if (n % 2 == 0 || n % 3 == 0)
			return false;

		for (long i = 5; i * i <= n; i = i + 6)
			if (n % i == 0 || n % (i + 2) == 0)
				return false;

		return true;
	}

	static String toString(int[] dp) {
		StringBuilder sb = new StringBuilder();
		for (int i = 0; i < dp.length; i++)
			sb.append(dp[i] + " ");
		return sb.toString();
	}
	
	static String toString(boolean[] dp) {
		StringBuilder sb = new StringBuilder();
		for (int i = 0; i < dp.length; i++)
			sb.append(dp[i] + " ");
		return sb.toString();
	}
	
	static String toString(long[] dp) {
		StringBuilder sb = new StringBuilder();
		for (int i = 0; i < dp.length; i++)
			sb.append(dp[i] + " ");
		return sb.toString();
	}
	
	static String toString(char[] dp) {
		StringBuilder sb = new StringBuilder();
		for (int i = 0; i < dp.length; i++)
			sb.append(dp[i] + "");
		return sb.toString();
	}
	
	static String toString(int[][] dp) {
		StringBuilder sb = new StringBuilder();
		for (int i = 0; i < dp.length; i++) {
			for (int j = 0; j < dp[i].length; j++) {
				sb.append(dp[i][j] + "");
			}
			sb.append('\n');
		}
		return sb.toString();
	}
	
	static String toString(long[][] dp) {
		StringBuilder sb = new StringBuilder();
		for (int i = 0; i < dp.length; i++) {
			for (int j = 0; j < dp[i].length; j++) {
				sb.append(dp[i][j] + " ");
			}
			sb.append('\n');
		}
		return sb.toString();
	}
	
	static String toString(double[][] dp) {
		StringBuilder sb = new StringBuilder();
		for (int i = 0; i < dp.length; i++) {
			for (int j = 0; j < dp[i].length; j++) {
				sb.append(dp[i][j] + " ");
			}
			sb.append('\n');
		}
		return sb.toString();
	}
	
	static String toString(char[][] dp) {
		StringBuilder sb = new StringBuilder();
		for (int i = 0; i < dp.length; i++) {
			for (int j = 0; j < dp[i].length; j++) {
				sb.append(dp[i][j] + " ");
			}
			sb.append('\n');
		}
		return sb.toString();
	}
	
	static char toChar(int i) {
		return (char) (i + 48);
	}
	
	static long mod(long a, long m) {
	    return (a%m + m) % m;
	}
	
	static long mod(long num) {
		return (num % gigamod + gigamod) % gigamod;
	}
	
	// Uses weighted quick-union with path compression.
	static class UnionFind {
	    private int[] parent;  // parent[i] = parent of i
	    private int[] size;    // size[i] = number of sites in tree rooted at i
	                           // Note: not necessarily correct if i is not a root node
	    private int count;     // number of components

	    public UnionFind(int n) {
	        count = n;
	        parent = new int[n];
	        size = new int[n];
	        for (int i = 0; i < n; i++) {
	            parent[i] = i;
	            size[i] = 1;
	        }
	    }

	    // Number of connected components.
	    public int count() {
	        return count;
	    }
	  
	    // Find the root of p.
	    public int find(int p) {
	        int root = p;
	        while (root != parent[root])
	            root = parent[root];
	        while (p != root) {
	            int newp = parent[p];
	            parent[p] = root;
	            p = newp;
	        }
	        return root;
	    }

	    public boolean connected(int p, int q) {
	        return find(p) == find(q);
	    }
	    
	    public int numConnectedTo(int node) {
	    	return size[find(node)];
	    }
	    
	    // Weighted union.
	    public void union(int p, int q) {
	        int rootP = find(p);
	        int rootQ = find(q);
	        
	        if (rootP == rootQ) return;

	        // make smaller root point to larger one
	        if (size[rootP] < size[rootQ]) {
	            parent[rootP] = rootQ;
	            size[rootQ] += size[rootP];
	        }
	        else {
	            parent[rootQ] = rootP;
	            size[rootP] += size[rootQ];
	        }
	        count--;
	    }
	    
	    public static int[] connectedComponents(UnionFind uf) {
	    	// We can do this in nlogn.
	    	
	    	int n = uf.size.length;
	    	int[] compoColors = new int[n];
	    	for (int i = 0; i < n; i++)
	    		compoColors[i] = uf.find(i);
	    	
	    	HashMap<Integer, Integer> oldToNew = new HashMap<>();
	    	int newCtr = 0;
	    	
	    	for (int i = 0; i < n; i++) {
	    		
	    		int thisOldColor = compoColors[i];
	    		Integer thisNewColor = oldToNew.get(thisOldColor);
	    		if (thisNewColor == null)
	    			thisNewColor = newCtr++;
	    		
	    		oldToNew.put(thisOldColor, thisNewColor);
	    		compoColors[i] = thisNewColor;
	    	}
	    	
	    	return compoColors;
	    }
	}
	
	static class UGraph {
		// Adjacency list.
		private TreeSet<Integer>[] adj;
		private static final String NEWLINE = "\n";
		private int E;
		
		public UGraph(int V) {
			adj = (TreeSet<Integer>[]) new TreeSet[V];
			E = 0;
			for (int i = 0; i < V; i++)
				adj[i] = new TreeSet<Integer>();
		}
		
		public void addEdge(int from, int to) {
			if (adj[from].contains(to)) return;
			E++;
			adj[from].add(to);
			adj[to].add(from);
		}
		
		public TreeSet<Integer> adj(int from) {
			return adj[from];
		}
		
		public int V() {
			return adj.length;
		}
		
		public int E() {
			return E;
		}
		
		public String toString() {
			StringBuilder s = new StringBuilder();
			s.append(V() + " vertices, " + E() + " edges " + NEWLINE);
			for (int v = 0; v < V(); v++) {
				s.append(v + ": ");
				for (int w : adj[v]) {
					s.append(w + " ");
				}
				s.append(NEWLINE);
			}
			return s.toString();
		}
		
		public static void dfsMark(int current, boolean[] marked, UGraph g) {
			if (marked[current]) return;
			
			marked[current] = true;
			Iterable<Integer> adj = g.adj(current);
			for (int adjc : adj)
				dfsMark(adjc, marked, g);
		}
		
		public static void dfsMark(int current, int from, long[] distTo, boolean[] marked, UGraph g, ArrayList<Integer> endPoints) {
			if (marked[current]) return;
			
			marked[current] = true;
			if (from != -1)
				distTo[current] = distTo[from] + 1;
			TreeSet<Integer> adj = g.adj(current);
			int alreadyMarkedCtr = 0;
			for (int adjc : adj) {
				if (marked[adjc]) alreadyMarkedCtr++;
				dfsMark(adjc, current, distTo, marked, g, endPoints);
			}
			
			if (alreadyMarkedCtr == adj.size())
				endPoints.add(current);
		}
		
		public static void bfsOrder(int current, UGraph g) {
		}
		
		public static void dfsMark(int current, int[] colorIds, int color, UGraph g) {
			if (colorIds[current] != -1) return;
			
			colorIds[current] = color;
			Iterable<Integer> adj = g.adj(current);
			for (int adjc : adj)
				dfsMark(adjc, colorIds, color, g);
		}
		
		public static int[] connectedComponents(UGraph g) {
			int n = g.V();
			int[] componentId = new int[n];
			Arrays.fill(componentId, -1);
			int colorCtr = 0;
			for (int i = 0; i < n; i++) {
				if (componentId[i] != -1) continue;
				dfsMark(i, componentId, colorCtr, g);
				colorCtr++;
			}
			
			return componentId;
		}
		
		public static boolean hasCycle(UGraph ug) {
			int n = ug.V();
			boolean[] marked = new boolean[n];
			boolean[] hasCycleFirst = new boolean[1];
			for (int i = 0; i < n; i++) {
				if (marked[i]) continue;
				hcDfsMark(i, ug, marked, hasCycleFirst, -1);
			}
			return hasCycleFirst[0];
		}
		
		// Helper for hasCycle.
		private static void hcDfsMark(int current, UGraph ug, boolean[] marked, boolean[] hasCycleFirst, int parent) {
			if (marked[current]) return;
			if (hasCycleFirst[0]) return;
			
			marked[current] = true;
			TreeSet<Integer> adjc = ug.adj(current);
			for (int adj : adjc) {
				if (marked[adj] && adj != parent && parent != -1) {
					hasCycleFirst[0] = true;
					return;
				}
				
				hcDfsMark(adj, ug, marked, hasCycleFirst, current);
			}
		}
	}
	
	static class Digraph {
		// Adjacency list.
		private HashSet<Integer>[] adj;
		private static final String NEWLINE = "\n";
		private int E;
		
		public Digraph(int V) {
			adj = (HashSet<Integer>[]) new HashSet[V];
			E = 0;
			for (int i = 0; i < V; i++)
				adj[i] = new HashSet<Integer>();
		}
		
		public void addEdge(int from, int to) {
			if (adj[from].contains(to)) return;
			E++;
			adj[from].add(to);
		}
		
		public HashSet<Integer> adj(int from) {
			return adj[from];
		}
		
		public int V() {
			return adj.length;
		}
		
		public int E() {
			return E;
		}
		
		public String toString() {
			StringBuilder s = new StringBuilder();
			s.append(V() + " vertices, " + E() + " edges " + NEWLINE);
			for (int v = 0; v < V(); v++) {
				s.append(v + ": ");
				for (int w : adj[v]) {
					s.append(w + " ");
				}
				s.append(NEWLINE);
			}
			return s.toString();
		}
		
		public static void dfsMark(int source, boolean[] marked, Digraph g) {
			if (marked[source]) return;
			
			marked[source] = true;
			Iterable<Integer> adj = g.adj(source);
			for (int adjc : adj)
				dfsMark(adjc, marked, g);
		}
		
		public static void bfsOrder(int source, Digraph g) {
		}
		
		private static void dfsMark(int source, int[] colorIds, int color, Digraph g) {
			if (colorIds[source] != -1) return;
			
			colorIds[source] = color;
			Iterable<Integer> adj = g.adj(source);
			for (int adjc : adj)
				dfsMark(adjc, colorIds, color, g);
		}
		
		public static int[] connectedComponents(Digraph g) {
			int n = g.V();
			int[] componentId = new int[n];
			Arrays.fill(componentId, -1);
			int colorCtr = 0;
			for (int i = 0; i < n; i++) {
				if (componentId[i] != -1) continue;
				dfsMark(i, componentId, colorCtr, g);
				colorCtr++;
			}
			
			return componentId;
		}
		
		public static Stack<Integer> topologicalSort(Digraph dg)
		{
			// dg has to be a directed acyclic graph.
			// We'll have to run dfs on the digraph and push the deepest nodes on stack first.
			// We'll need a Stack<Integer> and a int[] marked.
			Stack<Integer> topologicalStack = new Stack<Integer>();
			boolean[] marked = new boolean[dg.V()];
			
			// Calling dfs
			for (int i = 0; i < dg.V(); i++)
			{
				if (!marked[i]) runDfs(dg, topologicalStack, marked, i);
			}
			
			return topologicalStack;
		}
		
		static void runDfs(Digraph dg, Stack<Integer> topologicalStack, boolean[] marked, int source)
		{
			marked[source] = true;
			for (Integer adjVertex : dg.adj(source))
			{
				if (!marked[adjVertex]) runDfs(dg, topologicalStack, marked, adjVertex);
			}
			topologicalStack.add(source);
		}
	}
	
	static class FastReader {
		private BufferedReader bfr;
		private StringTokenizer st;

		public FastReader() {
			bfr = new BufferedReader(new InputStreamReader(System.in));
		}

		String next() {
			if (st == null || !st.hasMoreElements()) {
				try {
					st = new StringTokenizer(bfr.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
			return st.nextToken();
		}

		int nextInt() {
			return Integer.parseInt(next());
		}

		long nextLong() {
			return Long.parseLong(next());
		}

		double nextDouble() {
			return Double.parseDouble(next());
		}

		char nextChar() {
			return next().toCharArray()[0];
		}

		String nextString() {
			return next();
		}

		int[] nextIntArray(int n) {
			int[] arr = new int[n];
			for (int i = 0; i < n; i++)
				arr[i] = nextInt();
			return arr;
		}
		
		int[] nextOneIntArray(int n) {
			int[] arr = new int[n + 1];
			for (int i = 1; i < n; i++)
				arr[i] = nextInt();
			return arr;
		}

		double[] nextDoubleArray(int n) {
			double[] arr = new double[n];
			for (int i = 0; i < arr.length; i++)
				arr[i] = nextDouble();
			return arr;
		}

		long[] nextLongArray(int n) {
			long[] arr = new long[n];
			for (int i = 0; i < n; i++)
				arr[i] = nextLong();
			return arr;
		}
		
		/*public char[] nextCharArray(int n) {
			char[] chars = new char[n];
			for (int i = 0; i < n; i++)
				chars[i] = fr.nextChar();
			return chars;
		}*/
	}
	
	private static class IndexMaxPQ<Key extends Comparable<Key>> implements Iterable<Integer> {
	    private int maxN;        // maximum number of elements on PQ
	    private int n;           // number of elements on PQ
	    private int[] pq;        // binary heap using 1-based indexing
	    private int[] qp;        // inverse of pq - qp[pq[i]] = pq[qp[i]] = i
	    private Key[] keys;      // keys[i] = priority of i

	    public IndexMaxPQ(int maxN) {
	        if (maxN < 0) throw new IllegalArgumentException();
	        this.maxN = maxN;
	        n = 0;
	        keys = (Key[]) new Comparable[maxN + 1];    // make this of length maxN??
	        pq   = new int[maxN + 1];
	        qp   = new int[maxN + 1];                   // make this of length maxN??
	        for (int i = 0; i <= maxN; i++)
	            qp[i] = -1;
	    }

	    public boolean isEmpty() {
	        return n == 0;
	    }

	    public boolean contains(int i) {
	        validateIndex(i);
	        return qp[i] != -1;
	    }

	    public int size() {
	        return n;
	    }

	   /**
	     * Associate key with index i.
	     *
	     * @param  i an index
	     * @param  key the key to associate with index {@code i}
	     * @throws IllegalArgumentException unless {@code 0 <= i < maxN}
	     * @throws IllegalArgumentException if there already is an item
	     *         associated with index {@code i}
	     */
	    public void insert(int i, Key key) {
	        validateIndex(i);
	        if (contains(i)) throw new IllegalArgumentException("index is already in the priority queue");
	        n++;
	        qp[i] = n;
	        pq[n] = i;
	        keys[i] = key;
	        swim(n);
	    }

	    /**
	     * Returns an index associated with a maximum key.
	     *
	     * @return an index associated with a maximum key
	     * @throws NoSuchElementException if this priority queue is empty
	     */
	    public int maxIndex() {
	        if (n == 0) throw new NoSuchElementException("Priority queue underflow");
	        return pq[1];
	    }

	    /**
	     * Returns a maximum key.
	     *
	     * @return a maximum key
	     * @throws NoSuchElementException if this priority queue is empty
	     */
	    public Key maxKey() {
	        if (n == 0) throw new NoSuchElementException("Priority queue underflow");
	        return keys[pq[1]];
	    }

	    /**
	     * Removes a maximum key and returns its associated index.
	     *
	     * @return an index associated with a maximum key
	     * @throws NoSuchElementException if this priority queue is empty
	     */
	    public int delMax() {
	        if (n == 0) throw new NoSuchElementException("Priority queue underflow");
	        int max = pq[1];
	        exch(1, n--);
	        sink(1);

	        assert pq[n+1] == max;
	        qp[max] = -1;        // delete
	        keys[max] = null;    // to help with garbage collection
	        pq[n+1] = -1;        // not needed
	        return max;
	    }

	    /**
	     * Returns the key associated with index {@code i}.
	     *
	     * @param  i the index of the key to return
	     * @return the key associated with index {@code i}
	     * @throws IllegalArgumentException unless {@code 0 <= i < maxN}
	     * @throws NoSuchElementException no key is associated with index {@code i}
	     */
	    public Key keyOf(int i) {
	        validateIndex(i);
	        if (!contains(i)) throw new NoSuchElementException("index is not in the priority queue");
	        else return keys[i];
	    }

	    /**
	     * Change the key associated with index {@code i} to the specified value.
	     *
	     * @param  i the index of the key to change
	     * @param  key change the key associated with index {@code i} to this key
	     * @throws IllegalArgumentException unless {@code 0 <= i < maxN}
	     */
	    public void changeKey(int i, Key key) {
	        validateIndex(i);
	        if (!contains(i)) throw new NoSuchElementException("index is not in the priority queue");
	        keys[i] = key;
	        swim(qp[i]);
	        sink(qp[i]);
	    }

	    /**
	     * Increase the key associated with index {@code i} to the specified value.
	     *
	     * @param  i the index of the key to increase
	     * @param  key increase the key associated with index {@code i} to this key
	     * @throws IllegalArgumentException unless {@code 0 <= i < maxN}
	     * @throws IllegalArgumentException if {@code key <= keyOf(i)}
	     * @throws NoSuchElementException no key is associated with index {@code i}
	     */
	    public void increaseKey(int i, Key key) {
	        validateIndex(i);
	        if (!contains(i)) throw new NoSuchElementException("index is not in the priority queue");
	        if (keys[i].compareTo(key) == 0)
	            throw new IllegalArgumentException("Calling increaseKey() with a key equal to the key in the priority queue");
	        if (keys[i].compareTo(key) > 0)
	            throw new IllegalArgumentException("Calling increaseKey() with a key that is strictly less than the key in the priority queue");

	        keys[i] = key;
	        swim(qp[i]);
	    }

	    /**
	     * Decrease the key associated with index {@code i} to the specified value.
	     *
	     * @param  i the index of the key to decrease
	     * @param  key decrease the key associated with index {@code i} to this key
	     * @throws IllegalArgumentException unless {@code 0 <= i < maxN}
	     * @throws IllegalArgumentException if {@code key >= keyOf(i)}
	     * @throws NoSuchElementException no key is associated with index {@code i}
	     */
	    public void decreaseKey(int i, Key key) {
	        validateIndex(i);
	        if (!contains(i)) throw new NoSuchElementException("index is not in the priority queue");
	        if (keys[i].compareTo(key) == 0)
	            throw new IllegalArgumentException("Calling decreaseKey() with a key equal to the key in the priority queue");
	        if (keys[i].compareTo(key) < 0)
	            throw new IllegalArgumentException("Calling decreaseKey() with a key that is strictly greater than the key in the priority queue");
	        keys[i] = key;
	        sink(qp[i]);
	    }

	    /**
	     * Remove the key on the priority queue associated with index {@code i}.
	     *
	     * @param  i the index of the key to remove
	     * @throws IllegalArgumentException unless {@code 0 <= i < maxN}
	     * @throws NoSuchElementException no key is associated with index {@code i}
	     */
	    public void delete(int i) {
	        validateIndex(i);
	        if (!contains(i)) throw new NoSuchElementException("index is not in the priority queue");
	        int index = qp[i];
	        exch(index, n--);
	        swim(index);
	        sink(index);
	        keys[i] = null;
	        qp[i] = -1;
	    }

	    // throw an IllegalArgumentException if i is an invalid index
	    private void validateIndex(int i) {
	        if (i < 0) throw new IllegalArgumentException("index is negative: " + i);
	        if (i >= maxN) throw new IllegalArgumentException("index >= capacity: " + i);
	    }
	    
	    private boolean less(int i, int j) {
	        return keys[pq[i]].compareTo(keys[pq[j]]) < 0;
	    }

	    private void exch(int i, int j) {
	        int swap = pq[i];
	        pq[i] = pq[j];
	        pq[j] = swap;
	        qp[pq[i]] = i;
	        qp[pq[j]] = j;
	    }

	    private void swim(int k) {
	        while (k > 1 && less(k/2, k)) {
	            exch(k, k/2);
	            k = k/2;
	        }
	    }

	    private void sink(int k) {
	        while (2*k <= n) {
	            int j = 2*k;
	            if (j < n && less(j, j+1)) j++;
	            if (!less(k, j)) break;
	            exch(k, j);
	            k = j;
	        }
	    }


	    /**
	     * Returns an iterator that iterates over the keys on the
	     * priority queue in descending order.
	     * The iterator doesn't implement {@code remove()} since it's optional.
	     *
	     * @return an iterator that iterates over the keys in descending order
	     */
	    public Iterator<Integer> iterator() {
	        return new HeapIterator();
	    }

	    private class HeapIterator implements Iterator<Integer> {
	        // create a new pq
	        private IndexMaxPQ<Key> copy;

	        // add all elements to copy of heap
	        // takes linear time since already in heap order so no keys move
	        public HeapIterator() {
	            copy = new IndexMaxPQ<Key>(pq.length - 1);
	            for (int i = 1; i <= n; i++)
	                copy.insert(pq[i], keys[pq[i]]);
	        }

	        public boolean hasNext()  { return !copy.isEmpty();                     }
	        public void remove()      { throw new UnsupportedOperationException();  }

	        public Integer next() {
	            if (!hasNext()) throw new NoSuchElementException();
	            return copy.delMax();
	        }
	    }

	}
	
	public static class IndexMinPQ<Key extends Comparable<Key>> implements Iterable<Integer> {
	    private int maxN;        // maximum number of elements on PQ
	    private int n;           // number of elements on PQ
	    private int[] pq;        // binary heap using 1-based indexing
	    private int[] qp;        // inverse of pq - qp[pq[i]] = pq[qp[i]] = i
	    private Key[] keys;      // keys[i] = priority of i

	    public IndexMinPQ(int maxN) {
	        if (maxN < 0) throw new IllegalArgumentException();
	        this.maxN = maxN;
	        n = 0;
	        keys = (Key[]) new Comparable[maxN + 1];    // make this of length maxN??
	        pq   = new int[maxN + 1];
	        qp   = new int[maxN + 1];                   // make this of length maxN??
	        for (int i = 0; i <= maxN; i++)
	            qp[i] = -1;
	    }

	    public boolean isEmpty() {
	        return n == 0;
	    }

	    public boolean contains(int i) {
	        validateIndex(i);
	        return qp[i] != -1;
	    }

	    public int size() {
	        return n;
	    }

	    /**
	     * Associates key with index {@code i}.
	     *
	     * @param  i an index
	     * @param  key the key to associate with index {@code i}
	     * @throws IllegalArgumentException unless {@code 0 <= i < maxN}
	     * @throws IllegalArgumentException if there already is an item associated
	     *         with index {@code i}
	     */
	    public void insert(int i, Key key) {
	        validateIndex(i);
	        if (contains(i)) throw new IllegalArgumentException("index is already in the priority queue");
	        n++;
	        qp[i] = n;
	        pq[n] = i;
	        keys[i] = key;
	        swim(n);
	    }

	    /**
	     * Returns an index associated with a minimum key.
	     *
	     * @return an index associated with a minimum key
	     * @throws NoSuchElementException if this priority queue is empty
	     */
	    public int minIndex() {
	        if (n == 0) throw new NoSuchElementException("Priority queue underflow");
	        return pq[1];
	    }

	    /**
	     * Returns a minimum key.
	     *
	     * @return a minimum key
	     * @throws NoSuchElementException if this priority queue is empty
	     */
	    public Key minKey() {
	        if (n == 0) throw new NoSuchElementException("Priority queue underflow");
	        return keys[pq[1]];
	    }

	    /**
	     * Removes a minimum key and returns its associated index.
	     * @return an index associated with a minimum key
	     * @throws NoSuchElementException if this priority queue is empty
	     */
	    public int delMin() {
	        if (n == 0) throw new NoSuchElementException("Priority queue underflow");
	        int min = pq[1];
	        exch(1, n--);
	        sink(1);
	        assert min == pq[n+1];
	        qp[min] = -1;        // delete
	        keys[min] = null;    // to help with garbage collection
	        pq[n+1] = -1;        // not needed
	        return min;
	    }

	    /**
	     * Returns the key associated with index {@code i}.
	     *
	     * @param  i the index of the key to return
	     * @return the key associated with index {@code i}
	     * @throws IllegalArgumentException unless {@code 0 <= i < maxN}
	     * @throws NoSuchElementException no key is associated with index {@code i}
	     */
	    public Key keyOf(int i) {
	        validateIndex(i);
	        if (!contains(i)) throw new NoSuchElementException("index is not in the priority queue");
	        else return keys[i];
	    }

	    /**
	     * Change the key associated with index {@code i} to the specified value.
	     *
	     * @param  i the index of the key to change
	     * @param  key change the key associated with index {@code i} to this key
	     * @throws IllegalArgumentException unless {@code 0 <= i < maxN}
	     * @throws NoSuchElementException no key is associated with index {@code i}
	     */
	    public void changeKey(int i, Key key) {
	        validateIndex(i);
	        if (!contains(i)) throw new NoSuchElementException("index is not in the priority queue");
	        keys[i] = key;
	        swim(qp[i]);
	        sink(qp[i]);
	    }

	    /**
	     * Decrease the key associated with index {@code i} to the specified value.
	     *
	     * @param  i the index of the key to decrease
	     * @param  key decrease the key associated with index {@code i} to this key
	     * @throws IllegalArgumentException unless {@code 0 <= i < maxN}
	     * @throws IllegalArgumentException if {@code key >= keyOf(i)}
	     * @throws NoSuchElementException no key is associated with index {@code i}
	     */
	    public void decreaseKey(int i, Key key) {
	        validateIndex(i);
	        if (!contains(i)) throw new NoSuchElementException("index is not in the priority queue");
	        if (keys[i].compareTo(key) == 0)
	            throw new IllegalArgumentException("Calling decreaseKey() with a key equal to the key in the priority queue");
	        if (keys[i].compareTo(key) < 0)
	            throw new IllegalArgumentException("Calling decreaseKey() with a key strictly greater than the key in the priority queue");
	        keys[i] = key;
	        swim(qp[i]);
	    }

	    /**
	     * Increase the key associated with index {@code i} to the specified value.
	     *
	     * @param  i the index of the key to increase
	     * @param  key increase the key associated with index {@code i} to this key
	     * @throws IllegalArgumentException unless {@code 0 <= i < maxN}
	     * @throws IllegalArgumentException if {@code key <= keyOf(i)}
	     * @throws NoSuchElementException no key is associated with index {@code i}
	     */
	    public void increaseKey(int i, Key key) {
	        validateIndex(i);
	        if (!contains(i)) throw new NoSuchElementException("index is not in the priority queue");
	        if (keys[i].compareTo(key) == 0)
	            throw new IllegalArgumentException("Calling increaseKey() with a key equal to the key in the priority queue");
	        if (keys[i].compareTo(key) > 0)
	            throw new IllegalArgumentException("Calling increaseKey() with a key strictly less than the key in the priority queue");
	        keys[i] = key;
	        sink(qp[i]);
	    }

	    /**
	     * Remove the key associated with index {@code i}.
	     *
	     * @param  i the index of the key to remove
	     * @throws IllegalArgumentException unless {@code 0 <= i < maxN}
	     * @throws NoSuchElementException no key is associated with index {@code i}
	     */
	    public void delete(int i) {
	        validateIndex(i);
	        if (!contains(i)) throw new NoSuchElementException("index is not in the priority queue");
	        int index = qp[i];
	        exch(index, n--);
	        swim(index);
	        sink(index);
	        keys[i] = null;
	        qp[i] = -1;
	    }

	    // throw an IllegalArgumentException if i is an invalid index
	    private void validateIndex(int i) {
	        if (i < 0) throw new IllegalArgumentException("index is negative: " + i);
	        if (i >= maxN) throw new IllegalArgumentException("index >= capacity: " + i);
	    }

	    private boolean greater(int i, int j) {
	        return keys[pq[i]].compareTo(keys[pq[j]]) > 0;
	    }

	    private void exch(int i, int j) {
	        int swap = pq[i];
	        pq[i] = pq[j];
	        pq[j] = swap;
	        qp[pq[i]] = i;
	        qp[pq[j]] = j;
	    }

	    private void swim(int k) {
	        while (k > 1 && greater(k/2, k)) {
	            exch(k, k/2);
	            k = k/2;
	        }
	    }

	    private void sink(int k) {
	        while (2*k <= n) {
	            int j = 2*k;
	            if (j < n && greater(j, j+1)) j++;
	            if (!greater(k, j)) break;
	            exch(k, j);
	            k = j;
	        }
	    }


	   /***************************************************************************
	    * Iterators.
	    ***************************************************************************/

	    /**
	     * Returns an iterator that iterates over the keys on the
	     * priority queue in ascending order.
	     * The iterator doesn't implement {@code remove()} since it's optional.
	     *
	     * @return an iterator that iterates over the keys in ascending order
	     */
	    public Iterator<Integer> iterator() { return new HeapIterator(); }

	    private class HeapIterator implements Iterator<Integer> {
	        // create a new pq
	        private IndexMinPQ<Key> copy;

	        // add all elements to copy of heap
	        // takes linear time since already in heap order so no keys move
	        public HeapIterator() {
	            copy = new IndexMinPQ<Key>(pq.length - 1);
	            for (int i = 1; i <= n; i++)
	                copy.insert(pq[i], keys[pq[i]]);
	        }

	        public boolean hasNext()  { return !copy.isEmpty();                     }
	        public void remove()      { throw new UnsupportedOperationException();  }

	        public Integer next() {
	            if (!hasNext()) throw new NoSuchElementException();
	            return copy.delMin();
	        }
	    }

	}
	
	public static class SegmentTree {

	    private Node[] heap;
	    private long[] array;
	    private int size;

	    /**
	     * Time-Complexity:  O(n*log(n))
	     *
	     * @param array the Initialization array
	     */
	    public SegmentTree(long[] array) {
	        this.array = Arrays.copyOf(array, array.length);
	        //The max size of this array is about 2 * 2 ^ log2(n) + 1
	        size = (int) (2 * Math.pow(2.0, Math.floor((Math.log((double) array.length) / Math.log(2.0)) + 1)));
	        heap = new Node[size];
	        build(1, 0, array.length);
	    }


	    public int size() {
	        return array.length;
	    }

	    //Initialize the Nodes of the Segment tree
	    private void build(int v, int from, int size) {
	        heap[v] = new Node();
	        heap[v].from = from;
	        heap[v].to = from + size - 1;

	        if (size == 1) {
	            heap[v].sum = array[from];
	            heap[v].min = array[from];
	        } else {
	            //Build childs
	            build(2 * v, from, size / 2);
	            build(2 * v + 1, from + size / 2, size - size / 2);

	            heap[v].sum = heap[2 * v].sum + heap[2 * v + 1].sum;
	            //min = min of the children
	            heap[v].min = Math.min(heap[2 * v].min, heap[2 * v + 1].min);
	        }
	    }

	    /**
	     * Range Sum Query
	     *
	     * Time-Complexity: O(log(n))
	     *
	     * @param  from from index
	     * @param  to to index
	     * @return sum
	     */
	    public long rangeSum(int from, int to) {
	        return rangeSum(1, from, to);
	    }

	    private long rangeSum(int v, int from, int to) {
	        Node n = heap[v];

	        //If you did a range update that contained this node, you can infer the Sum without going down the tree
	        if (n.pendingVal != null && contains(n.from, n.to, from, to)) {
	            return (to - from + 1) * n.pendingVal;
	        }

	        if (contains(from, to, n.from, n.to)) {
	            return heap[v].sum;
	        }

	        if (intersects(from, to, n.from, n.to)) {
	            propagate(v);
	            long leftSum = rangeSum(2 * v, from, to);
	            long rightSum = rangeSum(2 * v + 1, from, to);

	            return leftSum + rightSum;
	        }

	        return 0;
	    }

	    /**
	     * Range Min Query
	     * 
	     * Time-Complexity: O(log(n))
	     *
	     * @param  from from index
	     * @param  to to index
	     * @return min
	     */
	    public long rangeMin(int from, int to) {
	        return rangeMin(1, from, to);
	    }

	    private long rangeMin(int v, int from, int to) {
	        Node n = heap[v];


	        //If you did a range update that contained this node, you can infer the Min value without going down the tree
	        if (n.pendingVal != null && contains(n.from, n.to, from, to)) {
	            return n.pendingVal;
	        }

	        if (contains(from, to, n.from, n.to)) {
	            return heap[v].min;
	        }

	        if (intersects(from, to, n.from, n.to)) {
	            propagate(v);
	            long leftMin = rangeMin(2 * v, from, to);
	            long rightMin = rangeMin(2 * v + 1, from, to);

	            return Math.min(leftMin, rightMin);
	        }

	        return Integer.MAX_VALUE;
	    }


	    /**
	     * Range Update Operation.
	     * With this operation you can update either one position or a range of positions with a given number.
	     * The update operations will update the less it can to update the whole range (Lazy Propagation).
	     * The values will be propagated lazily from top to bottom of the segment tree.
	     * This behavior is really useful for updates on portions of the array
	     * <p>
	     * Time-Complexity: O(log(n))
	     *
	     * @param from  from index
	     * @param to    to index
	     * @param value value
	     */
	    public void update(int from, int to, int value) {
	        update(1, from, to, value);
	    }

	    private void update(int v, int from, int to, int value) {

	        //The Node of the heap tree represents a range of the array with bounds: [n.from, n.to]
	        Node n = heap[v];

	        /**
	         * If the updating-range contains the portion of the current Node  We lazily update it.
	         * This means We do NOT update each position of the vector, but update only some temporal
	         * values into the Node; such values into the Node will be propagated down to its children only when they need to.
	         */
	        if (contains(from, to, n.from, n.to)) {
	            change(n, value);
	        }

	        if (n.size() == 1) return;

	        if (intersects(from, to, n.from, n.to)) {
	            /**
	             * Before keeping going down to the tree We need to propagate the
	             * the values that have been temporally/lazily saved into this Node to its children
	             * So that when We visit them the values  are properly updated
	             */
	            propagate(v);

	            update(2 * v, from, to, value);
	            update(2 * v + 1, from, to, value);

	            n.sum = heap[2 * v].sum + heap[2 * v + 1].sum;
	            n.min = Math.min(heap[2 * v].min, heap[2 * v + 1].min);
	        }
	    }
	    
	   /*public void rangeAdd(int tl, int tr, int l, int r, int add) {
	    	rangeAdd(1, tl, tr, l, r, add);
	    }
	    
	    private void rangeAdd(int v, int tl, int tr, int l, int r, int add) {
	        if (l > r)
	            return;
	        if (l == tl && r == tr) {
	            heap[v].sum += add;
	        } else {
	            int tm = (tl + tr) / 2;
	            rangeAdd(v*2, tl, tm, l, Math.min(r, tm), add);
	            rangeAdd(v*2+1, tm+1, tr, Math.max(l, tm+1), r, add);
	        }
	    }*/

	    //Propagate temporal values to children
	    private void propagate(int v) {
	        Node n = heap[v];

	        if (n.pendingVal != null) {
	            change(heap[2 * v], n.pendingVal);
	            change(heap[2 * v + 1], n.pendingVal);
	            n.pendingVal = null; //unset the pending propagation value
	        }
	    }

	    //Save the temporal values that will be propagated lazily
	    private void change(Node n, int value) {
	        n.pendingVal = value;
	        n.sum = n.size() * value;
	        n.min = value;
	        array[n.from] = value;

	    }

	    //Test if the range1 contains range2
	    private boolean contains(int from1, int to1, int from2, int to2) {
	        return from2 >= from1 && to2 <= to1;
	    }

	    //check inclusive intersection, test if range1[from1, to1] intersects range2[from2, to2]
	    private boolean intersects(int from1, int to1, int from2, int to2) {
	        return from1 <= from2 && to1 >= from2   //  (.[..)..] or (.[...]..)
	                || from1 >= from2 && from1 <= to2; // [.(..]..) or [..(..)..
	    }

	    //The Node class represents a partition range of the array.
	    static class Node {
	        long sum;
	        long min;
	        //Here We store the value that will be propagated lazily
	        Integer pendingVal = null;
	        int from;
	        int to;

	        int size() {
	            return to - from + 1;
	        }

	    }
	}
}

// NOTES: 
// ASCII VALUE OF 'A': 65
// ASCII VALUE OF 'a': 97
// Range of long: 9 * 10^18
// ASCII VALUE OF '0': 48