Student Valera is an undergraduate student at the University. His end of term exams are approaching and he is to pass exactly n exams. Valera is a smart guy, so he will be able to pass any exam he takes on his first try. Besides, he can take several exams on one day, and in any order.

According to the schedule, a student can take the exam for the i-th subject on the day number ai. However, Valera has made an arrangement with each teacher and the teacher of the i-th subject allowed him to take an exam before the schedule time on day bi (bi < ai). Thus, Valera can take an exam for the i-th subject either on day ai, or on day bi. All the teachers put the record of the exam in the student's record book on the day of the actual exam and write down the date of the mark as number ai.

Valera believes that it would be rather strange if the entries in the record book did not go in the order of non-decreasing date. Therefore Valera asks you to help him. Find the minimum possible value of the day when Valera can take the final exam if he takes exams so that all the records in his record book go in the order of non-decreasing date.

Input

The first line contains a single positive integer n (1 ≤ n ≤ 5000) — the number of exams Valera will take.

Each of the next n lines contains two positive space-separated integers ai and bi (1 ≤ bi < ai ≤ 109) — the date of the exam in the schedule and the early date of passing the i-th exam, correspondingly.

Output

Print a single integer — the minimum possible number of the day when Valera can take the last exam if he takes all the exams so that all the records in his record book go in the order of non-decreasing date.

Examples

Input

3
5 2
3 1
4 2


Output

2


Input

3
6 1
5 2
4 3


Output

6

Note

In the first sample Valera first takes an exam in the second subject on the first day (the teacher writes down the schedule date that is 3). On the next day he takes an exam in the third subject (the teacher writes down the schedule date, 4), then he takes an exam in the first subject (the teacher writes down the mark with date 5). Thus, Valera takes the last exam on the second day and the dates will go in the non-decreasing order: 3, 4, 5.

In the second sample Valera first takes an exam in the third subject on the fourth day. Then he takes an exam in the second subject on the fifth day. After that on the sixth day Valera takes an exam in the first subject.
import java.io.BufferedWriter;
import java.util.InputMismatchException;
import java.util.NoSuchElementException;
import java.math.BigInteger;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.Writer;
import java.io.IOException;
import java.util.Arrays;
import java.io.InputStream;
import java.io.OutputStreamWriter;
import java.util.Comparator;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 * @author Egor Kulikov (egor@egork.net)
 */
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);
		TaskA solver = new TaskA();
		solver.solve(1, in, out);
		out.close();
	}
}

class TaskA {
    public void solve(int testNumber, InputReader in, OutputWriter out) {
		int count = in.readInt();
		int[] normal = new int[count];
		int[] preliminary = new int[count];
		IOUtils.readIntArrays(in, normal, preliminary);
		int[] order = ArrayUtils.createOrder(count);
		ArrayUtils.sort(order, new IntComparator() {
			public int compare(int first, int second) {
				if (normal[first] != normal[second]) {
					return normal[first] - normal[second];
				}
				return preliminary[first] - preliminary[second];
			}
		});
		ArrayUtils.orderBy(ArrayUtils.reversePermutation(order), normal, preliminary);
		boolean canPreliminary = true;
		for (int i = 1; i < count; i++) {
			canPreliminary = canPreliminary && preliminary[i] >= preliminary[i - 1] || preliminary[i] >= normal[i - 1];
		}
		out.printLine(canPreliminary ? preliminary[count - 1] : normal[count - 1]);
    }
}

class InputReader {

	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 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 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;
	}

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

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

class IOUtils {

	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();
		}
	}

}

class ArrayUtils {
	private static int[] tempInt = new int[0];

	public static int[] createOrder(int size) {
		int[] order = new int[size];
		for (int i = 0; i < size; i++)
			order[i] = i;
		return order;
	}

	public static int[] sort(int[] array, IntComparator comparator) {
		return sort(array, 0, array.length, comparator);
	}

	public static int[] sort(int[] array, int from, int to, IntComparator comparator) {
		if (from == 0 && to == array.length)
			new IntArray(array).inPlaceSort(comparator);
		else
			new IntArray(array).subList(from, to).inPlaceSort(comparator);
		return array;
	}

	private static void ensureCapacityInt(int size) {
		if (tempInt.length >= size)
			return;
		size = Math.max(size, tempInt.length << 1);
		tempInt = new int[size];
	}

	public static int[] order(final int[] array) {
		return sort(createOrder(array.length), new IntComparator() {
			public int compare(int first, int second) {
				if (array[first] < array[second])
					return -1;
				if (array[first] > array[second])
					return 1;
				return 0;
			}
		});
	}

	public static int[] reversePermutation(int[] permutation) {
		int[] result = new int[permutation.length];
		for (int i = 0; i < permutation.length; i++)
			result[permutation[i]] = i;
		return result;
	}

	public static void orderBy(int[] base, int[]... arrays) {
		int[] order = ArrayUtils.order(base);
		order(order, base);
		for (int[] array : arrays)
			order(order, array);
	}

	public static void order(int[] order, int[] array) {
		ensureCapacityInt(order.length);
		for (int i = 0; i < order.length; i++)
			tempInt[i] = array[order[i]];
		System.arraycopy(tempInt, 0, array, 0, array.length);
	}

}

interface IntComparator {

	public int compare(int first, int second);
}

abstract class IntCollection {
	public abstract IntIterator iterator();
	public abstract int size();

}

interface IntIterator {
	public int value() throws NoSuchElementException;
	/*
	 * @throws NoSuchElementException only if iterator already invalid
	 */
	public void advance() throws NoSuchElementException;
	public boolean isValid();
}

abstract class IntList extends IntCollection implements Comparable<IntList> {
	private static final int INSERTION_THRESHOLD = 16;

	public abstract int get(int index);
	public abstract void set(int index, int value);

	public IntIterator iterator() {
		return new IntIterator() {
			private int size = size();
			private int index = 0;

			public int value() throws NoSuchElementException {
				if (!isValid())
					throw new NoSuchElementException();
				return get(index);
			}

			public void advance() throws NoSuchElementException {
				if (!isValid())
					throw new NoSuchElementException();
				index++;
			}

			public boolean isValid() {
				return index < size;
			}
		};
	}

	public IntList subList(final int from, final int to) {
		return new SubList(from, to);
	}

	private void swap(int first, int second) {
		if (first == second)
			return;
		int temp = get(first);
		set(first, get(second));
		set(second, temp);
	}

	public IntSortedList inPlaceSort(IntComparator comparator) {
		quickSort(0, size() - 1, (Integer.bitCount(Integer.highestOneBit(size()) - 1) * 5) >> 1, comparator);
		return new IntSortedArray(this, comparator);
	}

	private void quickSort(int from, int to, int remaining, IntComparator comparator) {
		if (to - from < INSERTION_THRESHOLD) {
			insertionSort(from, to, comparator);
			return;
		}
		if (remaining == 0) {
			heapSort(from, to, comparator);
			return;
		}
		remaining--;
		int pivotIndex = (from + to) >> 1;
		int pivot = get(pivotIndex);
		swap(pivotIndex, to);
		int storeIndex = from;
		int equalIndex = to;
		for (int i = from; i < equalIndex; i++) {
			int value = comparator.compare(get(i), pivot);
			if (value < 0)
				swap(storeIndex++, i);
			else if (value == 0)
				swap(--equalIndex, i--);
		}
		quickSort(from, storeIndex - 1, remaining, comparator);
		for (int i = equalIndex; i <= to; i++)
			swap(storeIndex++, i);
		quickSort(storeIndex, to, remaining, comparator);
	}

	private void heapSort(int from, int to, IntComparator comparator) {
		for (int i = (to + from - 1) >> 1; i >= from; i--)
			siftDown(i, to, comparator, from);
		for (int i = to; i > from; i--) {
			swap(from, i);
			siftDown(from, i - 1, comparator, from);
		}
	}

	private void siftDown(int start, int end, IntComparator comparator, int delta) {
		int value = get(start);
		while (true) {
			int child = ((start - delta) << 1) + 1 + delta;
			if (child > end)
				return;
			int childValue = get(child);
			if (child + 1 <= end) {
				int otherValue = get(child + 1);
				if (comparator.compare(otherValue, childValue) > 0) {
					child++;
					childValue = otherValue;
				}
			}
			if (comparator.compare(value, childValue) >= 0)
				return;
			swap(start, child);
			start = child;
		}
	}

	private void insertionSort(int from, int to, IntComparator comparator) {
		for (int i = from + 1; i <= to; i++) {
			int value = get(i);
			for (int j = i - 1; j >= from; j--) {
				if (comparator.compare(get(j), value) <= 0)
					break;
				swap(j, j + 1);
			}
		}
	}

	public int hashCode() {
		int hashCode = 1;
		for (IntIterator i = iterator(); i.isValid(); i.advance())
			hashCode = 31 * hashCode + i.value();
		return hashCode;
	}

	public boolean equals(Object obj) {
		if (!(obj instanceof IntList))
			return false;
		IntList list = (IntList)obj;
		if (list.size() != size())
			return false;
		IntIterator i = iterator();
		IntIterator j = list.iterator();
		while (i.isValid()) {
			if (i.value() != j.value())
				return false;
			i.advance();
			j.advance();
		}
		return true;
	}

	public int compareTo(IntList o) {
		IntIterator i = iterator();
		IntIterator j = o.iterator();
		while (true) {
			if (i.isValid()) {
				if (j.isValid()) {
					if (i.value() != j.value()) {
						if (i.value() < j.value())
							return -1;
						else
							return 1;
					}
				} else
					return 1;
			} else {
				if (j.isValid())
					return -1;
				else
					return 0;
			}
			i.advance();
			j.advance();
		}
	}

	private class SubList extends IntList {
        private final int to;
        private final int from;
        private int size;

        public SubList(int from, int to) {
            this.to = to;
            this.from = from;
            size = to - from;
        }

        public int get(int index) {
            if (index < 0 || index >= size)
                throw new IndexOutOfBoundsException();
            return IntList.this.get(index + from);
        }

        public void set(int index, int value) {
            if (index < 0 || index >= size)
                throw new IndexOutOfBoundsException();
            IntList.this.set(index + from, value);
        }

        public int size() {
            return size;
        }

	}
}

abstract class IntSortedList extends IntList {
	protected final IntComparator comparator;

	protected IntSortedList(IntComparator comparator) {
		this.comparator = comparator;
	}

	public void set(int index, int value) {
		throw new UnsupportedOperationException();
	}

	public IntSortedList inPlaceSort(IntComparator comparator) {
		if (comparator == this.comparator)
			return this;
		throw new UnsupportedOperationException();
	}

	protected void ensureSorted() {
		int size = size();
		if (size == 0)
			return;
		int last = get(0);
		for (int i = 1; i < size; i++) {
			int current = get(i);
			if (comparator.compare(last, current) > 0)
				throw new IllegalArgumentException();
			last = current;
		}
	}

	public IntSortedList subList(final int from, final int to) {
		return new IntSortedList(comparator) {
			private int size = to - from;

			public int get(int index) {
				if (index < 0 || index >= size)
					throw new IndexOutOfBoundsException();
				return IntSortedList.this.get(index + from);
			}

			public int size() {
				return size;
			}
		};
	}
}

class IntArray extends IntList {
	private final int[] array;

	public IntArray(int[] array) {
		this.array = array;
	}

	public int get(int index) {
		return array[index];
	}

	public void set(int index, int value) {
		array[index] = value;
	}

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

}

class IntSortedArray extends IntSortedList {
	private final int[] array;

	public IntSortedArray(IntCollection collection, IntComparator comparator) {
		super(comparator);
		array = new int[collection.size()];
		int i = 0;
		for (IntIterator iterator = collection.iterator(); iterator.isValid(); iterator.advance())
			array[i++] = iterator.value();
		ensureSorted();
	}

	public int get(int index) {
		return array[index];
	}

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

