Having written another programming contest, three Rabbits decided to grab some lunch. The coach gave the team exactly k time units for the lunch break.

The Rabbits have a list of n restaurants to lunch in: the i-th restaurant is characterized by two integers fi and ti. Value ti shows the time the Rabbits need to lunch in the i-th restaurant. If time ti exceeds the time k that the coach has given for the lunch break, then the Rabbits' joy from lunching in this restaurant will equal fi - (ti - k). Otherwise, the Rabbits get exactly fi units of joy.

Your task is to find the value of the maximum joy the Rabbits can get from the lunch, depending on the restaurant. The Rabbits must choose exactly one restaurant to lunch in. Note that the joy value isn't necessarily a positive value. 

Input

The first line contains two space-separated integers — n (1 ≤ n ≤ 104) and k (1 ≤ k ≤ 109) — the number of restaurants in the Rabbits' list and the time the coach has given them to lunch, correspondingly. Each of the next n lines contains two space-separated integers — fi (1 ≤ fi ≤ 109) and ti (1 ≤ ti ≤ 109) — the characteristics of the i-th restaurant.

Output

In a single line print a single integer — the maximum joy value that the Rabbits will get from the lunch. 

Examples

Input

2 5
3 3
4 5


Output

4


Input

4 6
5 8
3 6
2 3
2 2


Output

3


Input

1 5
1 7


Output

-1
import static java.lang.Math.*;

import java.io.*;
import java.lang.reflect.*;

public class A {

	final int MOD = (int)1e9 + 7;
	final double eps = 1e-12;
	final long INF = (long)1e18;
	
	public A () {
		int N = sc.nextInt();
		int K = sc.nextInt();
		Integer [][] FT = sc.nextInts(N);
		
		long res = -INF;
		for (Integer [] ft : FT)
			if (ft[1] > K)
				res = max(res, ft[0] - (ft[1] - K));
			else
				res = max(res, ft[0]);
				
		exit(res);
	}

	////////////////////////////////////////////////////////////////////////////////////

	/* Dear hacker, don't bother reading below this line, unless you want to help me debug my I/O routines :-) */
	
	static MyScanner sc = new MyScanner();
	
	static class MyScanner {
		public String next() {
			newLine();
			return line[index++];
		}
		
		public char nextChar() {
			return next().charAt(0);
		}
				
		public int nextInt() {
			return Integer.parseInt(next());
		}
		
		public long nextLong() {
			return Long.parseLong(next());
		}
		
		public double nextDouble() {
			return Double.parseDouble(next());
		}
		
		public String nextLine() {
			line = null;
			return readLine();
		}
		
		public String [] nextStrings() {
			line = null;
			return readLine().split(" ");
		}
		
		public char [] nextChars() {
			return next().toCharArray();
		}

		public Integer [] nextInts() {
			String [] L = nextStrings();
			Integer [] res = new Integer [L.length];
			for (int i = 0; i < L.length; ++i)
				res[i] = Integer.parseInt(L[i]);
			return res;
		}	
		
		public Long [] nextLongs() {
			String [] L = nextStrings();
			Long [] res = new Long [L.length];
			for (int i = 0; i < L.length; ++i)
				res[i] = Long.parseLong(L[i]);
			return res;
		}

		public Double [] nextDoubles() {
			String [] L = nextStrings();
			Double [] res = new Double [L.length];
			for (int i = 0; i < L.length; ++i)
				res[i] = Double.parseDouble(L[i]);
			return res;
		}

		public String [] next (int N) {
			String [] res = new String [N];
			for (int i = 0; i < N; ++i)
				res[i] = sc.next();
			return res;
		}
		
		public Integer [] nextInt (int N) {
			Integer [] res = new Integer [N];
			for (int i = 0; i < N; ++i)
				res[i] = sc.nextInt();
			return res;
		}		
		
		public Long [] nextLong (int N) {
			Long [] res = new Long [N];
			for (int i = 0; i < N; ++i)
				res[i] = sc.nextLong();
			return res;
		}		
		
		public Double [] nextDouble (int N) {
			Double [] res = new Double [N];
			for (int i = 0; i < N; ++i)
				res[i] = sc.nextDouble();
			return res;
		}		
		
		public String [][] nextStrings (int N) {
			String [][] res = new String [N][];
			for (int i = 0; i < N; ++i)
				res[i] = sc.nextStrings();
			return res;
		}
		
		public Integer [][] nextInts (int N) {
			Integer [][] res = new Integer [N][];
			for (int i = 0; i < N; ++i)
				res[i] = sc.nextInts();
			return res;
		}
		
		public Long [][] nextLongs (int N) {
			Long [][] res = new Long [N][];
			for (int i = 0; i < N; ++i)
				res[i] = sc.nextLongs();
			return res;
		}
		
		public Double [][] nextDoubles (int N) {
			Double [][] res = new Double [N][];
			for (int i = 0; i < N; ++i)
				res[i] = sc.nextDoubles();
			return res;
		}
		
		//////////////////////////////////////////////
		
		private boolean eol() {
			return index == line.length;
		}

		private String readLine() {
			try {
				return r.readLine();
			} catch (Exception e) {
				throw new Error(e);
			}
		}
		private final BufferedReader r;

		MyScanner () {
			this(new BufferedReader(new InputStreamReader(System.in)));
		}
		
		MyScanner(BufferedReader r) {
			try {
				this.r = r;
				while (!r.ready())
					Thread.sleep(1);
				start();
			} catch (Exception e) {
				throw new Error(e);
			}
		}
		
		private String [] line;
		private int index;

		private void newLine() {
			if (line == null || eol()) {
				line = readLine().split(" ");
				index = 0;
			}
		}		
	}
	
	static void print(Object o, Object... a) {
		printDelim(" ", o, a);
	}
	
	static void cprint(Object o, Object... a) {
		printDelim("", o, a);
	}
	
	static void printDelim (String delim, Object o, Object... a) {
		pw.println(build(delim, o, a));
	}

	static void exit (Object o, Object... a) {
		print(o, a);
		exit();
	}

	static void exit () {
		pw.close();
		System.out.flush();
		System.err.println("------------------");
		System.err.println("Time: " + ((millis() - t) / 1000.0));
		System.exit(0);
	}
	
	void NO() {
		throw new Error("NO!");
	}
	
	////////////////////////////////////////////////////////////////////////////////////
	
	static String build(String delim, Object o, Object... a) {
		StringBuilder b = new StringBuilder();
		append(b, o, delim);
		for (Object p : a)
			append(b, p, delim);
		return b.toString().trim();		
	}
	
	static void append(StringBuilder b, Object o, String delim) {
		if (o.getClass().isArray()) {
			int L = Array.getLength(o);
			for (int i = 0; i < L; ++i)
				append(b, Array.get(o, i), delim);
		} else if (o instanceof Iterable<?>) {
			for (Object p : (Iterable<?>)o)
				append(b, p, delim);
		} else
			b.append(delim).append(o);		
	}
	
	////////////////////////////////////////////////////////////////////////////////////
	
	public static void main(String[] args) {
		new A();
		exit();
	}

	static void start() {
		t = millis();
	}

	static PrintWriter pw = new PrintWriter(System.out);
	
	static long t;
	
	static long millis() {
		return System.currentTimeMillis();
	}	
}
