Problem: Nowadays, most of the internet advertisements are not statically linked to a web page. Instead, what will be shown to the person opening a web page is determined within 100 milliseconds after the web page is opened. Usually, multiple companies compete for each ad slot on the web page in an auction. Each of them receives a request with details about the user, web page and ad slot and they have to respond within those 100 milliseconds with a bid they would pay for putting an advertisement on that ad slot. The company that suggests the highest bid wins the auction and gets to place its advertisement. If there are several companies tied for the highest bid, the winner gets picked at random.

However, the company that won the auction does not have to pay the exact amount of its bid. In most of the cases, a second-price auction is used. This means that the amount paid by the company is equal to the maximum of all the other bids placed for this ad slot.

Let's consider one such bidding. There are n companies competing for placing an ad. The i-th of these companies will bid an integer number of microdollars equiprobably randomly chosen from the range between Li and Ri, inclusive. In the other words, the value of the i-th company bid can be any integer from the range [Li, Ri] with the same probability. 

Determine the expected value that the winner will have to pay in a second-price auction.

Input

The first line of input contains an integer number n (2 ≤ n ≤ 5). n lines follow, the i-th of them containing two numbers Li and Ri (1 ≤ Li ≤ Ri ≤ 10000) describing the i-th company's bid preferences.

This problem doesn't have subproblems. You will get 8 points for the correct submission.

Output

Output the answer with absolute or relative error no more than 1e - 9.

Examples

Input

3
4 7
8 10
5 5


Output

5.7500000000


Input

3
2 5
3 4
1 6


Output

3.5000000000

Note

Consider the first example. The first company bids a random integer number of microdollars in range [4, 7]; the second company bids between 8 and 10, and the third company bids 5 microdollars. The second company will win regardless of the exact value it bids, however the price it will pay depends on the value of first company's bid. With probability 0.5 the first company will bid at most 5 microdollars, and the second-highest price of the whole auction will be 5. With probability 0.25 it will bid 6 microdollars, and with probability 0.25 it will bid 7 microdollars. Thus, the expected value the second company will have to pay is 0.5·5 + 0.25·6 + 0.25·7 = 5.75.

Solution (in JAVA):

Solution:
import java.io.*;
import java.util.*;
import java.math.*;
import java.lang.reflect.*;

public class Main {
	public static void main(String[] args) {
		InputStream inputStream = System.in;
		OutputStream outputStream = System.out;
		InputReader in = new InputReader(inputStream);
		OutputWriter out = new OutputWriter(outputStream);
		Task solver = new Task();
		solver.solve(1, in, out);
		out.close();
	}
}

class Task {

	int[] from, to, flag;
	
	public void solve(int testNumber, InputReader in, OutputWriter out) {
		int n=in.readInt();
		from=new int[n];
		to=new int[n];
		flag=new int[n];
		IOUtils.readIntArrays(in, from, to);
		double ret=0;
		for (int i=1; i<=10000; i++) {
			double p=f(0, i, out);
			ret+=p*i;
//			if (i<=10) out.printLine(i, p);
		}
		out.printLine(ret);
	}
	
	double f(int pos, int v, OutputWriter out) {
		if (pos==flag.length){
			int x=0, y=0;
			for (int i: flag) {
				if (i==1) x++;
				else if (i==0) y++;
			}
			if (x>1 || x+y<2) return 0;
			double p=1;
			for (int i=0; i<flag.length; i++) {
				int j=flag[i];
				if (j<0) {
					if (from[i]>=v) return 0;
					p*=1.0*(MiscUtils.min(to[i], v-1)-from[i]+1)/(to[i]-from[i]+1);
				} else if (j==0) {
					if (from[i]>v || to[i]<v) return 0;
					p*=1.0/(to[i]-from[i]+1);
				} else {
					if (to[i]<=v) return 0;
					p*=1.0*(to[i]+1-MiscUtils.max(from[i], v+1))/(to[i]-from[i]+1);
				}
			}
//			if (v==6) {
//				out.printLine(flag);
//				out.printLine(p);
//			}
			return p;
		}
		double ret=0;
		for (int i=-1; i<2; i++) {
			flag[pos]=i;
			double temp=f(pos+1, v, out);
			ret+=temp;
		}
		return ret;
	}
}

class InputReader {
	private boolean finished = false;

	private InputStream stream;
	private byte[] buf = new byte[1024];
	private int curChar;
	private int numChars;
	private SpaceCharFilter filter;

	public InputReader(InputStream stream) {
		this.stream = stream;
	}

	public int read() {
		if (numChars == -1)
			throw new InputMismatchException();
		if (curChar >= numChars) {
			curChar = 0;
			try {
				numChars = stream.read(buf);
			} catch (IOException e) {
				throw new InputMismatchException();
			}
			if (numChars <= 0)
				return -1;
		}
		return buf[curChar++];
	}

	public int peek() {
		if (numChars == -1)
			return -1;
		if (curChar >= numChars) {
			curChar = 0;
			try {
				numChars = stream.read(buf);
			} catch (IOException e) {
				return -1;
			}
			if (numChars <= 0)
				return -1;
		}
		return buf[curChar];
	}

	public int readInt() {
		int c = read();
		while (isSpaceChar(c))
			c = read();
		int sgn = 1;
		if (c == '-') {
			sgn = -1;
			c = read();
		}
		int res = 0;
		do {
			if (c < '0' || c > '9')
				throw new InputMismatchException();
			res *= 10;
			res += c - '0';
			c = read();
		} while (!isSpaceChar(c));
		return res * sgn;
	}

	public long readLong() {
		int c = read();
		while (isSpaceChar(c))
			c = read();
		int sgn = 1;
		if (c == '-') {
			sgn = -1;
			c = read();
		}
		long res = 0;
		do {
			if (c < '0' || c > '9')
				throw new InputMismatchException();
			res *= 10;
			res += c - '0';
			c = read();
		} while (!isSpaceChar(c));
		return res * sgn;
	}

	public String readString() {
		int c = read();
		while (isSpaceChar(c))
			c = read();
		StringBuilder res = new StringBuilder();
		do {
			if (Character.isValidCodePoint(c))
				res.appendCodePoint(c);
			c = read();
		} while (!isSpaceChar(c));
		return res.toString();
	}

	public boolean isSpaceChar(int c) {
		if (filter != null)
			return filter.isSpaceChar(c);
		return isWhitespace(c);
	}

	public static boolean isWhitespace(int c) {
		return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
	}

	private String readLine0() {
		StringBuilder buf = new StringBuilder();
		int c = read();
		while (c != '\n' && c != -1) {
			if (c != '\r')
				buf.appendCodePoint(c);
			c = read();
		}
		return buf.toString();
	}

	public String readLine() {
		String s = readLine0();
		while (s.trim().length() == 0)
			s = readLine0();
		return s;
	}

	public String readLine(boolean ignoreEmptyLines) {
		if (ignoreEmptyLines)
			return readLine();
		else
			return readLine0();
	}

	public BigInteger readBigInteger() {
		try {
			return new BigInteger(readString());
		} catch (NumberFormatException e) {
			throw new InputMismatchException();
		}
	}

	public char readCharacter() {
		int c = read();
		while (isSpaceChar(c))
			c = read();
		return (char) c;
	}

	public double readDouble() {
		int c = read();
		while (isSpaceChar(c))
			c = read();
		int sgn = 1;
		if (c == '-') {
			sgn = -1;
			c = read();
		}
		double res = 0;
		while (!isSpaceChar(c) && c != '.') {
			if (c == 'e' || c == 'E')
				return res * Math.pow(10, readInt());
			if (c < '0' || c > '9')
				throw new InputMismatchException();
			res *= 10;
			res += c - '0';
			c = read();
		}
		if (c == '.') {
			c = read();
			double m = 1;
			while (!isSpaceChar(c)) {
				if (c == 'e' || c == 'E')
					return res * Math.pow(10, readInt());
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				m /= 10;
				res += (c - '0') * m;
				c = read();
			}
		}
		return res * sgn;
	}

	public boolean isExhausted() {
		int value;
		while (isSpaceChar(value = peek()) && value != -1)
			read();
		return value == -1;
	}

	public String next() {
		return readString();
	}

	public SpaceCharFilter getFilter() {
		return filter;
	}

	public void setFilter(SpaceCharFilter filter) {
		this.filter = filter;
	}

	public interface SpaceCharFilter {
		public boolean isSpaceChar(int ch);
	}
}

class OutputWriter {
	private final PrintWriter writer;

	public OutputWriter(OutputStream outputStream) {
		writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(
				outputStream)));
	}

	public OutputWriter(Writer writer) {
		this.writer = new PrintWriter(writer);
	}

	public void print(char[] array) {
		writer.print(array);
	}

	public void print(Object... objects) {
		for (int i = 0; i < objects.length; i++) {
			if (i != 0)
				writer.print(' ');
			writer.print(objects[i]);
		}
	}

	public void print(int[] array) {
		for (int i = 0; i < array.length; i++) {
			if (i != 0)
				writer.print(' ');
			writer.print(array[i]);
		}
	}

	public void print(long[] array) {
		for (int i = 0; i < array.length; i++) {
			if (i != 0)
				writer.print(' ');
			writer.print(array[i]);
		}
	}

	public void printLine(int[] array) {
		print(array);
		writer.println();
	}

	public void printLine(long[] array) {
		print(array);
		writer.println();
	}

	public void printLine() {
		writer.println();
	}

	public void printLine(Object... objects) {
		print(objects);
		writer.println();
	}

	public void print(char i) {
		writer.print(i);
	}

	public void printLine(char i) {
		writer.println(i);
	}

	public void printLine(char[] array) {
		writer.println(array);
	}

	public void printFormat(String format, Object... objects) {
		writer.printf(format, objects);
	}

	public void close() {
		writer.close();
	}

	public void flush() {
		writer.flush();
	}

	public void print(long i) {
		writer.print(i);
	}

	public void printLine(long i) {
		writer.println(i);
	}

	public void print(int i) {
		writer.print(i);
	}

	public void printLine(int i) {
		writer.println(i);
	}
}

class IOUtils {

	public static int[] readIntArray(InputReader in, int size) {
		int[] array = new int[size];
		for (int i = 0; i < size; i++)
			array[i] = in.readInt();
		return array;
	}

	public static long[] readLongArray(InputReader in, int size) {
		long[] array = new long[size];
		for (int i = 0; i < size; i++)
			array[i] = in.readLong();
		return array;
	}

	public static double[] readDoubleArray(InputReader in, int size) {
		double[] array = new double[size];
		for (int i = 0; i < size; i++)
			array[i] = in.readDouble();
		return array;
	}

	public static String[] readStringArray(InputReader in, int size) {
		String[] array = new String[size];
		for (int i = 0; i < size; i++)
			array[i] = in.readString();
		return array;
	}

	public static char[] readCharArray(InputReader in, int size) {
		char[] array = new char[size];
		for (int i = 0; i < size; i++)
			array[i] = in.readCharacter();
		return array;
	}

	public static void readIntArrays(InputReader in, int[]... arrays) {
		for (int i = 0; i < arrays[0].length; i++) {
			for (int j = 0; j < arrays.length; j++)
				arrays[j][i] = in.readInt();
		}
	}

	public static void readLongArrays(InputReader in, long[]... arrays) {
		for (int i = 0; i < arrays[0].length; i++) {
			for (int j = 0; j < arrays.length; j++)
				arrays[j][i] = in.readLong();
		}
	}

	public static void readDoubleArrays(InputReader in, double[]... arrays) {
		for (int i = 0; i < arrays[0].length; i++) {
			for (int j = 0; j < arrays.length; j++)
				arrays[j][i] = in.readDouble();
		}
	}

	public static char[][] readTable(InputReader in, int rowCount,
			int columnCount) {
		char[][] table = new char[rowCount][];
		for (int i = 0; i < rowCount; i++)
			table[i] = readCharArray(in, columnCount);
		return table;
	}

	public static int[][] readIntTable(InputReader in, int rowCount,
			int columnCount) {
		int[][] table = new int[rowCount][];
		for (int i = 0; i < rowCount; i++)
			table[i] = readIntArray(in, columnCount);
		return table;
	}

	public static double[][] readDoubleTable(InputReader in, int rowCount,
			int columnCount) {
		double[][] table = new double[rowCount][];
		for (int i = 0; i < rowCount; i++)
			table[i] = readDoubleArray(in, columnCount);
		return table;
	}

	public static long[][] readLongTable(InputReader in, int rowCount,
			int columnCount) {
		long[][] table = new long[rowCount][];
		for (int i = 0; i < rowCount; i++)
			table[i] = readLongArray(in, columnCount);
		return table;
	}

	public static String[][] readStringTable(InputReader in, int rowCount,
			int columnCount) {
		String[][] table = new String[rowCount][];
		for (int i = 0; i < rowCount; i++)
			table[i] = readStringArray(in, columnCount);
		return table;
	}

	public static String readText(InputReader in) {
		StringBuilder result = new StringBuilder();
		while (true) {
			int character = in.read();
			if (character == '\r')
				continue;
			if (character == -1)
				break;
			result.append((char) character);
		}
		return result.toString();
	}

	public static void readStringArrays(InputReader in, String[]... arrays) {
		for (int i = 0; i < arrays[0].length; i++) {
			for (int j = 0; j < arrays.length; j++)
				arrays[j][i] = in.readString();
		}
	}

	public static void printTable(OutputWriter out, char[][] table) {
		for (char[] row : table)
			out.printLine(new String(row));
	}
}

class SumIntervalTree extends LongIntervalTree {
	public SumIntervalTree(int size) {
		super(size);
	}

	@Override
	protected long joinValue(long left, long right) {
		return left + right;
	}

	@Override
	protected long joinDelta(long was, long delta) {
		return was + delta;
	}

	@Override
	protected long accumulate(long value, long delta, int length) {
		return value + delta * length;
	}

	@Override
	protected long neutralValue() {
		return 0;
	}

	@Override
	protected long neutralDelta() {
		return 0;
	}
}

abstract class IntervalTree {
	protected int size;

	protected IntervalTree(int size) {
		this(size, true);
	}

	public IntervalTree(int size, boolean shouldInit) {
		this.size = size;
		int nodeCount = Math.max(1, Integer.highestOneBit(size) << 2);
		initData(size, nodeCount);
		if (shouldInit)
			init();
	}

	protected abstract void initData(int size, int nodeCount);

	protected abstract void initAfter(int root, int left, int right, int middle);

	protected abstract void initBefore(int root, int left, int right, int middle);

	protected abstract void initLeaf(int root, int index);

	protected abstract void updatePostProcess(int root, int left, int right,
			int from, int to, long delta, int middle);

	protected abstract void updatePreProcess(int root, int left, int right,
			int from, int to, long delta, int middle);

	protected abstract void updateFull(int root, int left, int right, int from,
			int to, long delta);

	protected abstract long queryPostProcess(int root, int left, int right,
			int from, int to, int middle, long leftResult, long rightResult);

	protected abstract void queryPreProcess(int root, int left, int right,
			int from, int to, int middle);

	protected abstract long queryFull(int root, int left, int right, int from,
			int to);

	protected abstract long emptySegmentResult();

	public void init() {
		if (size == 0)
			return;
		init(0, 0, size - 1);
	}

	private void init(int root, int left, int right) {
		if (left == right) {
			initLeaf(root, left);
		} else {
			int middle = (left + right) >> 1;
			initBefore(root, left, right, middle);
			init(2 * root + 1, left, middle);
			init(2 * root + 2, middle + 1, right);
			initAfter(root, left, right, middle);
		}
	}

	public void update(int from, int to, long delta) {
		update(0, 0, size - 1, from, to, delta);
	}

	protected void update(int root, int left, int right, int from, int to,
			long delta) {
		if (left > to || right < from)
			return;
		if (left >= from && right <= to) {
			updateFull(root, left, right, from, to, delta);
			return;
		}
		int middle = (left + right) >> 1;
		updatePreProcess(root, left, right, from, to, delta, middle);
		update(2 * root + 1, left, middle, from, to, delta);
		update(2 * root + 2, middle + 1, right, from, to, delta);
		updatePostProcess(root, left, right, from, to, delta, middle);
	}

	public long query(int from, int to) {
		return query(0, 0, size - 1, from, to);
	}

	protected long query(int root, int left, int right, int from, int to) {
		if (left > to || right < from)
			return emptySegmentResult();
		if (left >= from && right <= to)
			return queryFull(root, left, right, from, to);
		int middle = (left + right) >> 1;
		queryPreProcess(root, left, right, from, to, middle);
		long leftResult = query(2 * root + 1, left, middle, from, to);
		long rightResult = query(2 * root + 2, middle + 1, right, from, to);
		return queryPostProcess(root, left, right, from, to, middle,
				leftResult, rightResult);
	}
}

abstract class LongIntervalTree extends IntervalTree {
	protected long[] value;
	protected long[] delta;

	protected LongIntervalTree(int size) {
		this(size, true);
	}

	public LongIntervalTree(int size, boolean shouldInit) {
		super(size, shouldInit);
	}

	@Override
	protected void initData(int size, int nodeCount) {
		value = new long[nodeCount];
		delta = new long[nodeCount];
	}

	protected abstract long joinValue(long left, long right);

	protected abstract long joinDelta(long was, long delta);

	protected abstract long accumulate(long value, long delta, int length);

	protected abstract long neutralValue();

	protected abstract long neutralDelta();

	protected long initValue(int index) {
		return neutralValue();
	}

	@Override
	protected void initAfter(int root, int left, int right, int middle) {
		value[root] = joinValue(value[2 * root + 1], value[2 * root + 2]);
		delta[root] = neutralDelta();
	}

	@Override
	protected void initBefore(int root, int left, int right, int middle) {
	}

	@Override
	protected void initLeaf(int root, int index) {
		value[root] = initValue(index);
		delta[root] = neutralDelta();
	}

	@Override
	protected void updatePostProcess(int root, int left, int right, int from,
			int to, long delta, int middle) {
		value[root] = joinValue(value[2 * root + 1], value[2 * root + 2]);
	}

	@Override
	protected void updatePreProcess(int root, int left, int right, int from,
			int to, long delta, int middle) {
		pushDown(root, left, middle, right);
	}

	protected void pushDown(int root, int left, int middle, int right) {
		value[2 * root + 1] = accumulate(value[2 * root + 1], delta[root],
				middle - left + 1);
		value[2 * root + 2] = accumulate(value[2 * root + 2], delta[root],
				right - middle);
		delta[2 * root + 1] = joinDelta(delta[2 * root + 1], delta[root]);
		delta[2 * root + 2] = joinDelta(delta[2 * root + 2], delta[root]);
		delta[root] = neutralDelta();
	}

	@Override
	protected void updateFull(int root, int left, int right, int from, int to,
			long delta) {
		value[root] = accumulate(value[root], delta, right - left + 1);
		this.delta[root] = joinDelta(this.delta[root], delta);
	}

	@Override
	protected long queryPostProcess(int root, int left, int right, int from,
			int to, int middle, long leftResult, long rightResult) {
		return joinValue(leftResult, rightResult);
	}

	@Override
	protected void queryPreProcess(int root, int left, int right, int from,
			int to, int middle) {
		pushDown(root, left, middle, right);
	}

	@Override
	protected long queryFull(int root, int left, int right, int from, int to) {
		return value[root];
	}

	@Override
	protected long emptySegmentResult() {
		return neutralValue();
	}
}

class IntPair implements Comparable<IntPair> {
	public final int first, second;

	public IntPair(int first, int second) {
		this.first = first;
		this.second = second;
	}

	@Override
	public String toString() {
		return "(" + first + "," + second + ")";
	}

	@Override
	public boolean equals(Object o) {
		if (this == o)
			return true;
		if (o == null || getClass() != o.getClass())
			return false;

		IntPair intPair = (IntPair) o;

		return first == intPair.first && second == intPair.second;

	}

	@Override
	public int hashCode() {
		int result = first;
		result = 31 * result + second;
		return result;
	}

	public int compareTo(IntPair o) {
		if (first < o.first)
			return -1;
		if (first > o.first)
			return 1;
		if (second < o.second)
			return -1;
		if (second > o.second)
			return 1;
		return 0;
	}
}

class Matrix {
	public static long mod = Long.MAX_VALUE;
	public final long[][] data;
	public final int rowCount;
	public final int columnCount;

	public Matrix(int rowCount, int columnCount) {
		this.rowCount = rowCount;
		this.columnCount = columnCount;
		this.data = new long[rowCount][columnCount];
	}

	public Matrix(long[][] data) {
		this.rowCount = data.length;
		this.columnCount = data[0].length;
		this.data = data;
	}

	public static Matrix add(Matrix first, Matrix second) {
		Matrix result = new Matrix(first.rowCount, first.columnCount);
		for (int i = 0; i < result.rowCount; i++) {
			for (int j = 0; j < result.columnCount; j++) {
				result.data[i][j] = first.data[i][j] + second.data[i][j];
				if (result.data[i][j] >= mod)
					result.data[i][j] -= mod;
			}
		}
		return result;
	}

	public static Matrix multiply(Matrix first, Matrix second) {
		Matrix result = new Matrix(first.rowCount, second.columnCount);
		for (int i = 0; i < first.rowCount; i++) {
			for (int j = 0; j < second.rowCount; j++) {
				for (int k = 0; k < second.columnCount; k++)
					result.data[i][k] = (result.data[i][k] + first.data[i][j]
							* second.data[j][k])
							% mod;
			}
		}
		return result;
	}

	public static Matrix fastMultiply(Matrix first, Matrix second) {
		Matrix result = new Matrix(first.rowCount, second.columnCount);
		for (int i = 0; i < first.rowCount; i++) {
			for (int j = 0; j < second.rowCount; j++) {
				for (int k = 0; k < second.columnCount; k++)
					result.data[i][k] += first.data[i][j] * second.data[j][k];
			}
		}
		for (int i = 0; i < first.rowCount; i++) {
			for (int j = 0; j < second.columnCount; j++)
				result.data[i][j] %= mod;
		}
		return result;
	}

	public static Matrix identityMatrix(int size) {
		Matrix result = new Matrix(size, size);
		for (int i = 0; i < size; i++)
			result.data[i][i] = 1;
		return result;
	}

	public static long[] convert(long[][] matrix) {
		long[] result = new long[matrix.length * matrix.length];
		for (int i = 0; i < matrix.length; i++) {
			for (int j = 0; j < matrix.length; j++)
				result[i * matrix.length + j] = matrix[i][j];
		}
		return result;
	}

	public static long[] sumPowers(long[] matrix, long exponent, long mod,
			int side) {
		long[] result = new long[matrix.length];
		long[] power = new long[matrix.length];
		long[] temp = new long[matrix.length];
		long[] temp2 = new long[matrix.length];
		sumPowers(matrix, result, power, temp, temp2, exponent + 1, mod, side);
		return result;
	}

	private static void sumPowers(long[] matrix, long[] result, long[] power,
			long[] temp, long[] temp2, long exponent, long mod, int side) {
		if (exponent == 0) {
			for (int i = 0; i < matrix.length; i += side + 1)
				power[i] = 1 % mod;
			return;
		}
		if ((exponent & 1) == 0) {
			sumPowers(matrix, result, temp, power, temp2, exponent >> 1, mod,
					side);
			multiply(temp2, result, temp, mod, side);
			add(result, temp2, mod, side);
			multiply(power, temp, temp, mod, side);
		} else {
			sumPowers(matrix, result, temp, power, temp2, exponent - 1, mod,
					side);
			add(result, temp, mod, side);
			multiply(power, temp, matrix, mod, side);
		}
	}

	public static long[][] convert(long[] matrix, int side) {
		long[][] result = new long[side][side];
		for (int i = 0; i < side; i++) {
			for (int j = 0; j < side; j++)
				result[i][j] = matrix[i * side + j];
		}
		return result;
	}

	public static long[] power(long[] matrix, long exponent, long mod, int side) {
		long[] result = new long[matrix.length];
		long[] temp = new long[result.length];
		power(matrix, result, temp, exponent, mod, side);
		return result;
	}

	private static void power(long[] matrix, long[] result, long[] temp,
			long exponent, long mod, int side) {
		if (exponent == 0) {
			for (int i = 0; i < matrix.length; i += side + 1)
				result[i] = 1 % mod;
			return;
		}
		if ((exponent & 1) == 0) {
			power(matrix, temp, result, exponent >> 1, mod, side);
			multiply(result, temp, temp, mod, side);
		} else {
			power(matrix, temp, result, exponent - 1, mod, side);
			multiply(result, temp, matrix, mod, side);
		}
	}

	public static void multiply(long[] c, long[] a, long[] b, long mod, int side) {
		Arrays.fill(c, 0);
		for (int i = 0; i < side; i++) {
			for (int j = 0; j < side; j++) {
				for (int k = 0; k < side; k++) {
					c[i * side + k] += a[i * side + j] * b[j * side + k];
					if ((j & 3) == 3) {
						c[i * side + k] %= mod;
					}
				}
			}
		}
		for (int i = 0; i < c.length; i++)
			c[i] %= mod;
	}

	public static void add(long[] c, long[] a, long mod, int side) {
		for (int i = 0; i < side; i++) {
			for (int j = 0; j < side; j++) {
				c[i * side + j] += a[i * side + j];
				if (c[i * side + j] >= mod)
					c[i * side + j] -= mod;
			}
		}
	}

	public static long[] fastPower(long[] matrix, long exponent, long mod,
			int side) {
		long[] result = new long[matrix.length];
		long[] temp = new long[result.length];
		fastPower(matrix, result, temp, exponent, mod, side);
		return result;
	}

	private static void fastPower(long[] matrix, long[] result, long[] temp,
			long exponent, long mod, int side) {
		if (exponent == 0) {
			for (int i = 0; i < matrix.length; i += side + 1)
				result[i] = 1;
			return;
		}
		if ((exponent & 1) == 0) {
			fastPower(matrix, temp, result, exponent >> 1, mod, side);
			fastMultiply(result, temp, temp, mod, side);
		} else {
			power(matrix, temp, result, exponent - 1, mod, side);
			fastMultiply(result, temp, matrix, mod, side);
		}
	}

	public static void fastMultiply(long[] c, long[] a, long[] b, long mod,
			int side) {
		Arrays.fill(c, 0);
		for (int i = 0; i < side; i++) {
			for (int j = 0; j < side; j++) {
				for (int k = 0; k < side; k++)
					c[i * side + k] += a[i * side + j] * b[j * side + k];
			}
		}
		for (int i = 0; i < c.length; i++)
			c[i] %= mod;
	}

	public Matrix power(long exponent) {
		if (exponent == 0)
			return identityMatrix(rowCount);
		if (exponent == 1)
			return this;
		Matrix result = power(exponent >> 1);
		result = multiply(result, result);
		if ((exponent & 1) == 1)
			result = multiply(result, this);
		return result;
	}

	public Matrix fastPower(long exponent) {
		if (exponent == 0)
			return identityMatrix(rowCount);
		if (exponent == 1)
			return this;
		Matrix result = power(exponent >> 1);
		result = fastMultiply(result, result);
		if ((exponent & 1) == 1)
			result = fastMultiply(result, this);
		return result;
	}
}

class MiscUtils {
	public static final int[] DX4 = { 1, 0, -1, 0 };
	public static final int[] DY4 = { 0, -1, 0, 1 };
	public static final int[] DX8 = { 1, 1, 1, 0, -1, -1, -1, 0 };
	public static final int[] DY8 = { -1, 0, 1, 1, 1, 0, -1, -1 };
	public static final int[] DX_KNIGHT = { 2, 1, -1, -2, -2, -1, 1, 2 };
	public static final int[] DY_KNIGHT = { 1, 2, 2, 1, -1, -2, -2, -1 };

	private static final String[] ROMAN_TOKENS = { "M", "CM", "D", "CD", "C",
			"XC", "L", "XL", "X", "IX", "V", "IV", "I" };
	private static final int[] ROMAN_VALUES = { 1000, 900, 500, 400, 100, 90,
			50, 40, 10, 9, 5, 4, 1 };

	public static long josephProblem(long n, int k) {
		if (n == 1)
			return 0;
		if (k == 1)
			return n - 1;
		if (k > n)
			return (josephProblem(n - 1, k) + k) % n;
		long count = n / k;
		long result = josephProblem(n - count, k);
		result -= n % k;
		if (result < 0)
			result += n;
		else
			result += result / (k - 1);
		return result;
	}

	public static boolean isValidCell(int row, int column, int rowCount,
			int columnCount) {
		return row >= 0 && row < rowCount && column >= 0
				&& column < columnCount;
	}

	public static long maximalRectangleSum(long[][] array) {
		int n = array.length;
		int m = array[0].length;
		long[][] partialSums = new long[n + 1][m + 1];
		for (int i = 0; i < n; i++) {
			long rowSum = 0;
			for (int j = 0; j < m; j++) {
				rowSum += array[i][j];
				partialSums[i + 1][j + 1] = partialSums[i][j + 1] + rowSum;
			}
		}
		long result = Long.MIN_VALUE;
		for (int i = 0; i < m; i++) {
			for (int j = i; j < m; j++) {
				long minPartialSum = 0;
				for (int k = 1; k <= n; k++) {
					long current = partialSums[k][j + 1] - partialSums[k][i];
					result = Math.max(result, current - minPartialSum);
					minPartialSum = Math.min(minPartialSum, current);
				}
			}
		}
		return result;
	}

	public static int parseIP(String ip) {
		String[] components = ip.split("[.]");
		int result = 0;
		for (int i = 0; i < 4; i++)
			result += (1 << (24 - 8 * i)) * Integer.parseInt(components[i]);
		return result;
	}

	public static String buildIP(int mask) {
		StringBuilder result = new StringBuilder();
		for (int i = 0; i < 4; i++) {
			if (i != 0)
				result.append('.');
			result.append(mask >> (24 - 8 * i) & 255);
		}
		return result.toString();
	}

	public static <T> boolean equals(T first, T second) {
		return first == null && second == null || first != null
				&& first.equals(second);
	}

	public static boolean isVowel(char ch) {
		ch = Character.toUpperCase(ch);
		return ch == 'A' || ch == 'E' || ch == 'I' || ch == 'O' || ch == 'U'
				|| ch == 'Y';
	}

	public static boolean isStrictVowel(char ch) {
		ch = Character.toUpperCase(ch);
		return ch == 'A' || ch == 'E' || ch == 'I' || ch == 'O' || ch == 'U';
	}

	public static String convertToRoman(int number) {
		StringBuilder result = new StringBuilder();
		for (int i = 0; i < ROMAN_TOKENS.length; i++) {
			while (number >= ROMAN_VALUES[i]) {
				number -= ROMAN_VALUES[i];
				result.append(ROMAN_TOKENS[i]);
			}
		}
		return result.toString();
	}

	public static int convertFromRoman(String number) {
		int result = 0;
		for (int i = 0; i < ROMAN_TOKENS.length; i++) {
			while (number.startsWith(ROMAN_TOKENS[i])) {
				number = number.substring(ROMAN_TOKENS[i].length());
				result += ROMAN_VALUES[i];
			}
		}
		return result;
	}

	public static int distance(int x1, int y1, int x2, int y2) {
		int dx = x1 - x2;
		int dy = y1 - y2;
		return dx * dx + dy * dy;
	}

	public static <T extends Comparable<T>> T min(T first, T second) {
		if (first.compareTo(second) <= 0)
			return first;
		return second;
	}

	public static <T extends Comparable<T>> T max(T first, T second) {
		if (first.compareTo(second) <= 0)
			return second;
		return first;
	}

	public static void decreaseByOne(int[]... arrays) {
		for (int[] array : arrays) {
			for (int i = 0; i < array.length; i++)
				array[i]--;
		}
	}

	public static int[] getIntArray(String s) {
		String[] tokens = s.split(" ");
		int[] result = new int[tokens.length];
		for (int i = 0; i < result.length; i++)
			result[i] = Integer.parseInt(tokens[i]);
		return result;
	}
}

class Graph {
	public static final int REMOVED_BIT = 0;

	protected int vertexCount;
	protected int edgeCount;

	private int[] firstOutbound;
	private int[] firstInbound;

	private Edge[] edges;
	private int[] nextInbound;
	private int[] nextOutbound;
	private int[] from;
	private int[] to;
	private long[] weight;
	public long[] capacity;
	private int[] reverseEdge;
	private int[] flags;

	public Graph(int vertexCount) {
		this(vertexCount, vertexCount);
	}

	public Graph(int vertexCount, int edgeCapacity) {
		this.vertexCount = vertexCount;
		firstOutbound = new int[vertexCount];
		Arrays.fill(firstOutbound, -1);

		from = new int[edgeCapacity];
		to = new int[edgeCapacity];
		nextOutbound = new int[edgeCapacity];
		flags = new int[edgeCapacity];
	}

	public static Graph createGraph(int vertexCount, int[] from, int[] to) {
		Graph graph = new Graph(vertexCount, from.length);
		for (int i = 0; i < from.length; i++)
			graph.addSimpleEdge(from[i], to[i]);
		return graph;
	}

	public static Graph createWeightedGraph(int vertexCount, int[] from,
			int[] to, long[] weight) {
		Graph graph = new Graph(vertexCount, from.length);
		for (int i = 0; i < from.length; i++)
			graph.addWeightedEdge(from[i], to[i], weight[i]);
		return graph;
	}

	public static Graph createFlowGraph(int vertexCount, int[] from, int[] to,
			long[] capacity) {
		Graph graph = new Graph(vertexCount, from.length * 2);
		for (int i = 0; i < from.length; i++)
			graph.addFlowEdge(from[i], to[i], capacity[i]);
		return graph;
	}

	public static Graph createFlowWeightedGraph(int vertexCount, int[] from,
			int[] to, long[] weight, long[] capacity) {
		Graph graph = new Graph(vertexCount, from.length * 2);
		for (int i = 0; i < from.length; i++)
			graph.addFlowWeightedEdge(from[i], to[i], weight[i], capacity[i]);
		return graph;
	}

	public static Graph createTree(int[] parent) {
		Graph graph = new Graph(parent.length + 1, parent.length);
		for (int i = 0; i < parent.length; i++)
			graph.addSimpleEdge(parent[i], i + 1);
		return graph;
	}

	public int addEdge(int fromID, int toID, long weight, long capacity,
			int reverseEdge) {
		ensureEdgeCapacity(edgeCount + 1);
		if (firstOutbound[fromID] != -1)
			nextOutbound[edgeCount] = firstOutbound[fromID];
		else
			nextOutbound[edgeCount] = -1;
		firstOutbound[fromID] = edgeCount;
		if (firstInbound != null) {
			if (firstInbound[toID] != -1)
				nextInbound[edgeCount] = firstInbound[toID];
			else
				nextInbound[edgeCount] = -1;
			firstInbound[toID] = edgeCount;
		}
		this.from[edgeCount] = fromID;
		this.to[edgeCount] = toID;
		if (capacity != 0) {
			if (this.capacity == null)
				this.capacity = new long[from.length];
			this.capacity[edgeCount] = capacity;
		}
		if (weight != 0) {
			if (this.weight == null)
				this.weight = new long[from.length];
			this.weight[edgeCount] = weight;
		}
		if (reverseEdge != -1) {
			if (this.reverseEdge == null) {
				this.reverseEdge = new int[from.length];
				Arrays.fill(this.reverseEdge, 0, edgeCount, -1);
			}
			this.reverseEdge[edgeCount] = reverseEdge;
		}
		if (edges != null)
			edges[edgeCount] = createEdge(edgeCount);
		return edgeCount++;
	}

	protected final GraphEdge createEdge(int id) {
		return new GraphEdge(id);
	}

	public final int addFlowWeightedEdge(int from, int to, long weight,
			long capacity) {
		if (capacity == 0) {
			return addEdge(from, to, weight, 0, -1);
		} else {
			int lastEdgeCount = edgeCount;
			addEdge(to, from, -weight, 0, lastEdgeCount + entriesPerEdge());
			return addEdge(from, to, weight, capacity, lastEdgeCount);
		}
	}

	protected int entriesPerEdge() {
		return 1;
	}

	public final int addFlowEdge(int from, int to, long capacity) {
		return addFlowWeightedEdge(from, to, 0, capacity);
	}

	public final int addWeightedEdge(int from, int to, long weight) {
		return addFlowWeightedEdge(from, to, weight, 0);
	}

	public final int addSimpleEdge(int from, int to) {
		return addWeightedEdge(from, to, 0);
	}

	public final int vertexCount() {
		return vertexCount;
	}

	public final int edgeCount() {
		return edgeCount;
	}

	protected final int edgeCapacity() {
		return from.length;
	}

	public final Edge edge(int id) {
		initEdges();
		return edges[id];
	}

	public final int firstOutbound(int vertex) {
		int id = firstOutbound[vertex];
		while (id != -1 && isRemoved(id))
			id = nextOutbound[id];
		return id;
	}

	public final int nextOutbound(int id) {
		id = nextOutbound[id];
		while (id != -1 && isRemoved(id))
			id = nextOutbound[id];
		return id;
	}

	public final int firstInbound(int vertex) {
		initInbound();
		int id = firstInbound[vertex];
		while (id != -1 && isRemoved(id))
			id = nextInbound[id];
		return id;
	}

	public final int nextInbound(int id) {
		initInbound();
		id = nextInbound[id];
		while (id != -1 && isRemoved(id))
			id = nextInbound[id];
		return id;
	}

	public final int source(int id) {
		return from[id];
	}

	public final int destination(int id) {
		return to[id];
	}

	public final long weight(int id) {
		if (weight == null)
			return 0;
		return weight[id];
	}

	public final long capacity(int id) {
		if (capacity == null)
			return 0;
		return capacity[id];
	}

	public final long flow(int id) {
		if (reverseEdge == null)
			return 0;
		return capacity[reverseEdge[id]];
	}

	public final void pushFlow(int id, long flow) {
		if (flow == 0)
			return;
		if (flow > 0) {
			if (capacity(id) < flow)
				throw new IllegalArgumentException("Not enough capacity");
		} else {
			if (flow(id) < -flow)
				throw new IllegalArgumentException("Not enough capacity");
		}
		capacity[id] -= flow;
		capacity[reverseEdge[id]] += flow;
	}

	public int transposed(int id) {
		return -1;
	}

	public final int reverse(int id) {
		if (reverseEdge == null)
			return -1;
		return reverseEdge[id];
	}

	public final void addVertices(int count) {
		ensureVertexCapacity(vertexCount + count);
		Arrays.fill(firstOutbound, vertexCount, vertexCount + count, -1);
		if (firstInbound != null)
			Arrays.fill(firstInbound, vertexCount, vertexCount + count, -1);
		vertexCount += count;
	}

	protected final void initEdges() {
		if (edges == null) {
			edges = new Edge[from.length];
			for (int i = 0; i < edgeCount; i++)
				edges[i] = createEdge(i);
		}
	}

	public final void removeVertex(int vertex) {
		int id = firstOutbound[vertex];
		while (id != -1) {
			removeEdge(id);
			id = nextOutbound[id];
		}
		initInbound();
		id = firstInbound[vertex];
		while (id != -1) {
			removeEdge(id);
			id = nextInbound[id];
		}
	}

	private void initInbound() {
		if (firstInbound == null) {
			firstInbound = new int[firstOutbound.length];
			Arrays.fill(firstInbound, 0, vertexCount, -1);
			nextInbound = new int[from.length];
			for (int i = 0; i < edgeCount; i++) {
				nextInbound[i] = firstInbound[to[i]];
				firstInbound[to[i]] = i;
			}
		}
	}

	public final boolean flag(int id, int bit) {
		return (flags[id] >> bit & 1) != 0;
	}

	public final void setFlag(int id, int bit) {
		flags[id] |= 1 << bit;
	}

	public final void removeFlag(int id, int bit) {
		flags[id] &= -1 - (1 << bit);
	}

	public final void removeEdge(int id) {
		setFlag(id, REMOVED_BIT);
	}

	public final void restoreEdge(int id) {
		removeFlag(id, REMOVED_BIT);
	}

	public final boolean isRemoved(int id) {
		return flag(id, REMOVED_BIT);
	}

	public final Iterable<Edge> outbound(final int id) {
		initEdges();
		return new Iterable<Edge>() {
			public Iterator<Edge> iterator() {
				return new EdgeIterator(id, firstOutbound, nextOutbound);
			}
		};
	}

	public final Iterable<Edge> inbound(final int id) {
		initEdges();
		initInbound();
		return new Iterable<Edge>() {
			public Iterator<Edge> iterator() {
				return new EdgeIterator(id, firstInbound, nextInbound);
			}
		};
	}

	protected void ensureEdgeCapacity(int size) {
		if (from.length < size) {
			int newSize = Math.max(size, 2 * from.length);
			if (edges != null)
				edges = resize(edges, newSize);
			from = resize(from, newSize);
			to = resize(to, newSize);
			nextOutbound = resize(nextOutbound, newSize);
			if (nextInbound != null)
				nextInbound = resize(nextInbound, newSize);
			if (weight != null)
				weight = resize(weight, newSize);
			if (capacity != null)
				capacity = resize(capacity, newSize);
			if (reverseEdge != null)
				reverseEdge = resize(reverseEdge, newSize);
			flags = resize(flags, newSize);
		}
	}

	private void ensureVertexCapacity(int size) {
		if (firstOutbound.length < size) {
			int newSize = Math.max(size, 2 * from.length);
			firstOutbound = resize(firstOutbound, newSize);
			if (firstInbound != null)
				firstInbound = resize(firstInbound, newSize);
		}
	}

	protected final int[] resize(int[] array, int size) {
		int[] newArray = new int[size];
		System.arraycopy(array, 0, newArray, 0, array.length);
		return newArray;
	}

	private long[] resize(long[] array, int size) {
		long[] newArray = new long[size];
		System.arraycopy(array, 0, newArray, 0, array.length);
		return newArray;
	}

	private Edge[] resize(Edge[] array, int size) {
		Edge[] newArray = new Edge[size];
		System.arraycopy(array, 0, newArray, 0, array.length);
		return newArray;
	}

	public final boolean isSparse() {
		return vertexCount == 0 || edgeCount * 20 / vertexCount <= vertexCount;
	}

	protected class GraphEdge implements Edge {
		protected int id;

		protected GraphEdge(int id) {
			this.id = id;
		}

		public int getSource() {
			return source(id);
		}

		public int getDestination() {
			return destination(id);
		}

		public long getWeight() {
			return weight(id);
		}

		public long getCapacity() {
			return capacity(id);
		}

		public long getFlow() {
			return flow(id);
		}

		public void pushFlow(long flow) {
			Graph.this.pushFlow(id, flow);
		}

		public boolean getFlag(int bit) {
			return flag(id, bit);
		}

		public void setFlag(int bit) {
			Graph.this.setFlag(id, bit);
		}

		public void removeFlag(int bit) {
			Graph.this.removeFlag(id, bit);
		}

		public int getTransposedID() {
			return transposed(id);
		}

		public Edge getTransposedEdge() {
			int reverseID = getTransposedID();
			if (reverseID == -1)
				return null;
			initEdges();
			return edge(reverseID);
		}

		public int getReverseID() {
			return reverse(id);
		}

		public Edge getReverseEdge() {
			int reverseID = getReverseID();
			if (reverseID == -1)
				return null;
			initEdges();
			return edge(reverseID);
		}

		public int getID() {
			return id;
		}

		public void remove() {
			removeEdge(id);
		}

		public void restore() {
			restoreEdge(id);
		}
	}

	public class EdgeIterator implements Iterator<Edge> {
		private int edgeID;
		private final int[] next;
		private int lastID = -1;

		public EdgeIterator(int id, int[] first, int[] next) {
			this.next = next;
			edgeID = nextEdge(first[id]);
		}

		private int nextEdge(int id) {
			while (id != -1 && isRemoved(id))
				id = next[id];
			return id;
		}

		public boolean hasNext() {
			return edgeID != -1;
		}

		public Edge next() {
			if (edgeID == -1)
				throw new NoSuchElementException();
			lastID = edgeID;
			edgeID = nextEdge(next[lastID]);
			return edges[lastID];
		}

		public void remove() {
			if (lastID == -1)
				throw new IllegalStateException();
			removeEdge(lastID);
			lastID = -1;
		}
	}

}

class MaxFlow {
	private final Graph graph;
	private int source;
	private int destination;
	private int[] queue;
	private int[] distance;
	private int[] nextEdge;

	private MaxFlow(Graph graph, int source, int destination) {
		this.graph = graph;
		this.source = source;
		this.destination = destination;
		int vertexCount = graph.vertexCount();
		queue = new int[vertexCount];
		distance = new int[vertexCount];
		nextEdge = new int[vertexCount];
	}

	public static long dinic(Graph graph, int source, int destination) {
		return new MaxFlow(graph, source, destination).dinic();
	}

	private long dinic() {
		long totalFlow = 0;
		while (true) {
			edgeDistances();
			if (distance[destination] == -1)
				break;
			Arrays.fill(nextEdge, -2);
			totalFlow += dinicImpl(source, Long.MAX_VALUE);
		}
		return totalFlow;
	}

	private void edgeDistances() {
		Arrays.fill(distance, -1);
		distance[source] = 0;
		int size = 1;
		queue[0] = source;
		for (int i = 0; i < size; i++) {
			int current = queue[i];
			int id = graph.firstOutbound(current);
			while (id != -1) {
				if (graph.capacity(id) != 0) {
					int next = graph.destination(id);
					if (distance[next] == -1) {
						distance[next] = distance[current] + 1;
						queue[size++] = next;
					}
				}
				id = graph.nextOutbound(id);
			}
		}
	}

	private long dinicImpl(int source, long flow) {
		if (source == destination)
			return flow;
		if (flow == 0 || distance[source] == distance[destination])
			return 0;
		int id = nextEdge[source];
		if (id == -2)
			nextEdge[source] = id = graph.firstOutbound(source);
		long totalPushed = 0;
		while (id != -1) {
			int nextDestinationID = graph.destination(id);
			if (graph.capacity(id) != 0
					&& distance[nextDestinationID] == distance[source] + 1) {
				long pushed = dinicImpl(nextDestinationID,
						Math.min(flow, graph.capacity(id)));
				if (pushed != 0) {
					graph.pushFlow(id, pushed);
					flow -= pushed;
					totalPushed += pushed;
					if (flow == 0)
						return totalPushed;
				}
			}
			nextEdge[source] = id = graph.nextOutbound(id);
		}
		return totalPushed;
	}
}

interface Edge {
	public int getSource();

	public int getDestination();

	public long getWeight();

	public long getCapacity();

	public long getFlow();

	public void pushFlow(long flow);

	public boolean getFlag(int bit);

	public void setFlag(int bit);

	public void removeFlag(int bit);

	public int getTransposedID();

	public Edge getTransposedEdge();

	public int getReverseID();

	public Edge getReverseEdge();

	public int getID();

	public void remove();

	public void restore();
}

class Point {
	public static final Point ORIGIN = new Point(0, 0);
	public final double x;
	public final double y;

	@Override
	public String toString() {
		return "(" + x + ", " + y + ")";
	}

	public Point(double x, double y) {
		this.x = x;
		this.y = y;
	}

	public Line line(Point other) {
		if (equals(other))
			return null;
		double a = other.y - y;
		double b = x - other.x;
		double c = -a * x - b * y;
		return new Line(a, b, c);
	}

	@Override
	public boolean equals(Object o) {
		if (this == o)
			return true;
		if (o == null || getClass() != o.getClass())
			return false;

		Point point = (Point) o;

		return Math.abs(x - point.x) <= GeometryUtils.epsilon
				&& Math.abs(y - point.y) <= GeometryUtils.epsilon;
	}

	@Override
	public int hashCode() {
		int result;
		long temp;
		temp = x != +0.0d ? Double.doubleToLongBits(x) : 0L;
		result = (int) (temp ^ (temp >>> 32));
		temp = y != +0.0d ? Double.doubleToLongBits(y) : 0L;
		result = 31 * result + (int) (temp ^ (temp >>> 32));
		return result;
	}

	public double distance(Point other) {
		return GeometryUtils.fastHypot(x - other.x, y - other.y);
	}

	public double distance(Line line) {
		return Math.abs(line.a * x + line.b * y + line.c);
	}

	public double value() {
		return GeometryUtils.fastHypot(x, y);
	}

	public double angle() {
		return Math.atan2(y, x);
	}

	public static Point readPoint(InputReader in) {
		double x = in.readDouble();
		double y = in.readDouble();
		return new Point(x, y);
	}

	public Point rotate(double angle) {
		double nx = x * Math.cos(angle) - y * Math.sin(angle);
		double ny = y * Math.cos(angle) + x * Math.sin(angle);
		return new Point(nx, ny);
	}
}

class Line {
	public final double a;
	public final double b;
	public final double c;

	public Line(Point p, double angle) {
		a = Math.sin(angle);
		b = -Math.cos(angle);
		c = -p.x * a - p.y * b;
	}

	public Line(double a, double b, double c) {
		double h = GeometryUtils.fastHypot(a, b);
		this.a = a / h;
		this.b = b / h;
		this.c = c / h;
	}

	public Point intersect(Line other) {
		if (parallel(other))
			return null;
		double determinant = b * other.a - a * other.b;
		double x = (c * other.b - b * other.c) / determinant;
		double y = (a * other.c - c * other.a) / determinant;
		return new Point(x, y);
	}

	public boolean parallel(Line other) {
		return Math.abs(a * other.b - b * other.a) < GeometryUtils.epsilon;
	}

	public boolean contains(Point point) {
		return Math.abs(value(point)) < GeometryUtils.epsilon;
	}

	public Line perpendicular(Point point) {
		return new Line(-b, a, b * point.x - a * point.y);
	}

	public double value(Point point) {
		return a * point.x + b * point.y + c;
	}

	public double distance(Point center) {
		return Math.abs(value(center));
	}

	@Override
	public boolean equals(Object o) {
		if (this == o)
			return true;
		if (o == null || getClass() != o.getClass())
			return false;

		Line line = (Line) o;

		if (!parallel(line))
			return false;
		if (Math.abs(a * line.c - c * line.a) > GeometryUtils.epsilon
				|| Math.abs(b * line.c - c * line.b) > GeometryUtils.epsilon)
			return false;

		return true;
	}
}

class GeometryUtils {
	public static double epsilon = 1e-8;

	public static double fastHypot(double... x) {
		if (x.length == 0)
			return 0;
		else if (x.length == 1)
			return Math.abs(x[0]);
		else {
			double sumSquares = 0;
			for (double value : x)
				sumSquares += value * value;
			return Math.sqrt(sumSquares);
		}
	}

	public static double fastHypot(double x, double y) {
		return Math.sqrt(x * x + y * y);
	}

	public static double fastHypot(double[] x, double[] y) {
		if (x.length == 0)
			return 0;
		else if (x.length == 1)
			return Math.abs(x[0] - y[0]);
		else {
			double sumSquares = 0;
			for (int i = 0; i < x.length; i++) {
				double diff = x[i] - y[i];
				sumSquares += diff * diff;
			}
			return Math.sqrt(sumSquares);
		}
	}

	public static double fastHypot(int[] x, int[] y) {
		if (x.length == 0)
			return 0;
		else if (x.length == 1)
			return Math.abs(x[0] - y[0]);
		else {
			double sumSquares = 0;
			for (int i = 0; i < x.length; i++) {
				double diff = x[i] - y[i];
				sumSquares += diff * diff;
			}
			return Math.sqrt(sumSquares);
		}
	}

	public static double missileTrajectoryLength(double v, double angle,
			double g) {
		return (v * v * Math.sin(2 * angle)) / g;
	}

	public static double sphereVolume(double radius) {
		return 4 * Math.PI * radius * radius * radius / 3;
	}

	public static double triangleSquare(double first, double second,
			double third) {
		double p = (first + second + third) / 2;
		return Math.sqrt(p * (p - first) * (p - second) * (p - third));
	}

	public static double canonicalAngle(double angle) {
		while (angle > Math.PI)
			angle -= 2 * Math.PI;
		while (angle < -Math.PI)
			angle += 2 * Math.PI;
		return angle;
	}

	public static double positiveAngle(double angle) {
		while (angle > 2 * Math.PI - GeometryUtils.epsilon)
			angle -= 2 * Math.PI;
		while (angle < -GeometryUtils.epsilon)
			angle += 2 * Math.PI;
		return angle;
	}
}

class IntegerUtils {
	public static long gcd(long a, long b) {
		a = Math.abs(a);
		b = Math.abs(b);
		while (b != 0) {
			long temp = a % b;
			a = b;
			b = temp;
		}
		return a;
	}

	public static int gcd(int a, int b) {
		a = Math.abs(a);
		b = Math.abs(b);
		while (b != 0) {
			int temp = a % b;
			a = b;
			b = temp;
		}
		return a;
	}

	public static boolean[] generatePrimalityTable(int upTo) {
		boolean[] isPrime = new boolean[upTo];
		if (upTo < 2)
			return isPrime;
		Arrays.fill(isPrime, true);
		isPrime[0] = isPrime[1] = false;
		for (int i = 2; i * i < upTo; i++) {
			if (isPrime[i]) {
				for (int j = i * i; j < upTo; j += i)
					isPrime[j] = false;
			}
		}
		return isPrime;
	}

	public static int[] generateBitPrimalityTable(int upTo) {
		int[] isPrime = new int[(upTo + 31) >> 5];
		if (upTo < 2)
			return isPrime;
		Arrays.fill(isPrime, -1);
		isPrime[0] &= -4;
		for (int i = 2; i * i < upTo; i++) {
			if ((isPrime[i >> 5] >>> (i & 31) & 1) == 1) {
				for (int j = i * i; j < upTo; j += i)
					isPrime[j >> 5] &= -1 - (1 << (j & 31));
			}
		}
		return isPrime;
	}

	public static int[] generateDivisorTable(int upTo) {
		int[] divisor = new int[upTo];
		for (int i = 1; i < upTo; i++)
			divisor[i] = i;
		for (int i = 2; i * i < upTo; i++) {
			if (divisor[i] == i) {
				for (int j = i * i; j < upTo; j += i)
					divisor[j] = i;
			}
		}
		return divisor;
	}

	public static long powerInFactorial(long n, long p) {
		long result = 0;
		while (n != 0) {
			result += n /= p;
		}
		return result;
	}

	public static int sumDigits(CharSequence number) {
		int result = 0;
		for (int i = number.length() - 1; i >= 0; i--)
			result += digitValue(number.charAt(i));
		return result;
	}

	public static int digitValue(char digit) {
		if (Character.isDigit(digit))
			return digit - '0';
		if (Character.isUpperCase(digit))
			return digit + 10 - 'A';
		return digit + 10 - 'a';
	}

	public static int longCompare(long a, long b) {
		if (a < b)
			return -1;
		if (a > b)
			return 1;
		return 0;
	}

	public static long[][] generateBinomialCoefficients(int n) {
		long[][] result = new long[n + 1][n + 1];
		for (int i = 0; i <= n; i++) {
			result[i][0] = 1;
			for (int j = 1; j <= i; j++)
				result[i][j] = result[i - 1][j - 1] + result[i - 1][j];
		}
		return result;
	}

	public static long[][] generateBinomialCoefficients(int n, long module) {
		long[][] result = new long[n + 1][n + 1];
		if (module == 1)
			return result;
		for (int i = 0; i <= n; i++) {
			result[i][0] = 1;
			for (int j = 1; j <= i; j++) {
				result[i][j] = result[i - 1][j - 1] + result[i - 1][j];
				if (result[i][j] >= module)
					result[i][j] -= module;
			}
		}
		return result;
	}

	public static long[] generateBinomialRow(int n, long module) {
		long[] result = generateReverse(n + 1, module);
		result[0] = 1;
		for (int i = 1; i <= n; i++)
			result[i] = result[i - 1] * (n - i + 1) % module * result[i]
					% module;
		return result;
	}

	public static int[] representationInBase(long number, int base) {
		long basePower = base;
		int exponent = 1;
		while (number >= basePower) {
			basePower *= base;
			exponent++;
		}
		int[] representation = new int[exponent];
		for (int i = 0; i < exponent; i++) {
			basePower /= base;
			representation[i] = (int) (number / basePower);
			number %= basePower;
		}
		return representation;
	}

	public static int trueDivide(int a, int b) {
		return (a - trueMod(a, b)) / b;
	}

	public static long trueDivide(long a, long b) {
		return (a - trueMod(a, b)) / b;
	}

	public static int trueMod(int a, int b) {
		a %= b;
		a += b;
		a %= b;
		return a;
	}

	public static long trueMod(long a, long b) {
		a %= b;
		a += b;
		a %= b;
		return a;
	}

	public static long factorial(int n) {
		long result = 1;
		for (int i = 2; i <= n; i++)
			result *= i;
		return result;
	}

	public static long factorial(int n, long mod) {
		long result = 1;
		for (int i = 2; i <= n; i++)
			result = result * i % mod;
		return result % mod;
	}

	public static long power(long base, long exponent) {
		if (exponent == 0)
			return 1;
		long result = power(base, exponent >> 1);
		result = result * result;
		if ((exponent & 1) != 0)
			result = result * base;
		return result;
	}

	public static long power(long base, long exponent, long mod) {
		if (base >= mod)
			base %= mod;
		if (exponent == 0)
			return 1 % mod;
		long result = power(base, exponent >> 1, mod);
		result = result * result % mod;
		if ((exponent & 1) != 0)
			result = result * base % mod;
		return result;
	}

	public static long lcm(long a, long b) {
		return a / gcd(a, b) * b;
	}

	public static long[] generateFibonacci(long upTo) {
		int count = 0;
		long last = 0;
		long current = 1;
		while (current <= upTo) {
			long next = last + current;
			last = current;
			current = next;
			count++;
		}
		return generateFibonacci(count, -1);
	}

	public static long[] generateFibonacci(int count, long module) {
		long[] result = new long[count];
		if (module == -1) {
			if (count != 0)
				result[0] = 1;
			if (count > 1)
				result[1] = 1;
			for (int i = 2; i < count; i++)
				result[i] = result[i - 1] + result[i - 2];
		} else {
			if (count != 0)
				result[0] = 1 % module;
			if (count > 1)
				result[1] = 1 % module;
			for (int i = 2; i < count; i++)
				result[i] = (result[i - 1] + result[i - 2]) % module;
		}
		return result;
	}

	public static long[] generateHappy(int digits) {
		long[] happy = new long[(1 << (digits + 1)) - 2];
		happy[0] = 4;
		happy[1] = 7;
		int first = 0;
		int last = 2;
		for (int i = 2; i <= digits; i++) {
			for (int j = 0; j < last - first; j++) {
				happy[last + 2 * j] = 10 * happy[first + j] + 4;
				happy[last + 2 * j + 1] = 10 * happy[first + j] + 7;
			}
			int next = last + 2 * (last - first);
			first = last;
			last = next;
		}
		return happy;
	}

	public static long[] generateFactorial(int count, long module) {
		long[] result = new long[count];
		if (module == -1) {
			if (count != 0)
				result[0] = 1;
			for (int i = 1; i < count; i++)
				result[i] = result[i - 1] * i;
		} else {
			if (count != 0)
				result[0] = 1 % module;
			for (int i = 1; i < count; i++)
				result[i] = (result[i - 1] * i) % module;
		}
		return result;
	}

	public static long reverse(long number, long module) {
		return power(number, module - 2, module);
	}

	public static boolean isPrime(long number) {
		if (number < 2)
			return false;
		for (long i = 2; i * i <= number; i++) {
			if (number % i == 0)
				return false;
		}
		return true;
	}

	public static long[] generateReverse(int upTo, long module) {
		long[] result = new long[upTo];
		if (upTo > 1)
			result[1] = 1;
		for (int i = 2; i < upTo; i++)
			result[i] = (module - module / i * result[((int) (module % i))]
					% module)
					% module;
		return result;
	}

	public static long[] generateReverseFactorials(int upTo, long module) {
		long[] result = generateReverse(upTo, module);
		if (upTo > 0)
			result[0] = 1;
		for (int i = 1; i < upTo; i++)
			result[i] = result[i] * result[i - 1] % module;
		return result;
	}

	public static long[] generatePowers(long base, int count, long mod) {
		long[] result = new long[count];
		if (count != 0)
			result[0] = 1 % mod;
		for (int i = 1; i < count; i++)
			result[i] = result[i - 1] * base % mod;
		return result;
	}

	public static long nextPrime(long from) {
		if (from <= 2)
			return 2;
		from += 1 - (from & 1);
		while (!isPrime(from))
			from += 2;
		return from;
	}

	public static long binomialCoefficient(int n, int m, long mod) {
		if (m < 0 || m > n)
			return 0;
		if (2 * m > n)
			m = n - m;
		long result = 1;
		for (int i = n - m + 1; i <= n; i++)
			result = result * i % mod;
		return result
				* BigInteger.valueOf(factorial(m, mod))
						.modInverse(BigInteger.valueOf(mod)).longValue() % mod;
	}

	public static boolean isSquare(long number) {
		long sqrt = Math.round(Math.sqrt(number));
		return sqrt * sqrt == number;
	}

	public static long findCommon(long aRemainder, long aMod, long bRemainder,
			long bMod) {
		long modGCD = gcd(aMod, bMod);
		long gcdRemainder = aRemainder % modGCD;
		if (gcdRemainder != bRemainder % modGCD)
			return -1;
		aMod /= modGCD;
		aRemainder /= modGCD;
		bMod /= modGCD;
		bRemainder /= modGCD;
		long aReverse = BigInteger.valueOf(aMod)
				.modInverse(BigInteger.valueOf(bMod)).longValue();
		long bReverse = BigInteger.valueOf(bMod)
				.modInverse(BigInteger.valueOf(aMod)).longValue();
		long mod = aMod * bMod;
		return BigInteger
				.valueOf(bReverse * aRemainder % mod)
				.multiply(BigInteger.valueOf(bMod))
				.add(BigInteger.valueOf(aReverse * bRemainder % mod).multiply(
						BigInteger.valueOf(aMod))).mod(BigInteger.valueOf(mod))
				.longValue()
				* modGCD + gcdRemainder;
	}

	public static long[] generatePowers(long base, long maxValue) {
		if (maxValue <= 0)
			return new long[0];
		int size = 1;
		long current = 1;
		while (maxValue / base >= current) {
			current *= base;
			size++;
		}
		return generatePowers(base, size, Long.MAX_VALUE);
	}
}

class GraphAlgorithms {
	public static int[] topologicalSort(Graph graph) {
		int count = graph.vertexCount();
		int[] queue = new int[count];
		int[] degree = new int[count];
		int size = 0;
		for (int i = 0; i < graph.edgeCount(); i++) {
			if (!graph.isRemoved(i))
				degree[graph.destination(i)]++;
		}
		for (int i = 0; i < count; i++) {
			if (degree[i] == 0)
				queue[size++] = i;
		}
		for (int i = 0; i < size; i++) {
			int current = queue[i];
			for (int j = graph.firstOutbound(current); j != -1; j = graph
					.nextOutbound(j)) {
				int next = graph.destination(j);
				if (--degree[next] == 0)
					queue[size++] = next;
			}
		}
		if (size != count)
			return null;
		return queue;
	}
}