Problem: A TV show called "Guess a number!" is gathering popularity. The whole Berland, the old and the young, are watching the show.

The rules are simple. The host thinks of an integer y and the participants guess it by asking questions to the host. There are four types of acceptable questions:

  * Is it true that y is strictly larger than number x? 
  * Is it true that y is strictly smaller than number x? 
  * Is it true that y is larger than or equal to number x? 
  * Is it true that y is smaller than or equal to number x? 



On each question the host answers truthfully, "yes" or "no".

Given the sequence of questions and answers, find any integer value of y that meets the criteria of all answers. If there isn't such value, print "Impossible".

Input

The first line of the input contains a single integer n (1 ≤ n ≤ 10000) — the number of questions (and answers). Next n lines each contain one question and one answer to it. The format of each line is like that: "sign x answer", where the sign is:

  * ">" (for the first type queries), 
  * "<" (for the second type queries), 
  * ">=" (for the third type queries), 
  * "<=" (for the fourth type queries). 



All values of x are integer and meet the inequation  - 109 ≤ x ≤ 109. The answer is an English letter "Y" (for "yes") or "N" (for "no").

Consequtive elements in lines are separated by a single space.

Output

Print any of such integers y, that the answers to all the queries are correct. The printed number y must meet the inequation  - 2·109 ≤ y ≤ 2·109. If there are many answers, print any of them. If such value doesn't exist, print word "Impossible" (without the quotes).

Examples

Input

4
&gt;= 1 Y
&lt; 3 N
&lt;= -3 N
&gt; 55 N


Output

17


Input

2
&gt; 100 Y
&lt; -100 Y


Output

Impossible

Solution (in JAVA):

Solution:
import java.io.*;
import java.util.*;

public class GuessANumber {
    public static void main(String args[]) throws IOException
    {
        Scanner sc = new Scanner(System.in);
        
        int n = Integer.parseInt(sc.next());
        
        Specification specification = new Specification();

        for (int i=0; i<n; i++) {
            String sign = sc.next();
            long number = Long.parseLong(sc.next());
            String answer = sc.next();
            specification.addSpec(sign, number, answer); 
            if (!specification.canGuess()) {
                break;
            }
        }

        if (specification.canGuess()) {
            System.out.println(specification.guess());
        } else {
            System.out.println("Impossible");
        }
    }
}

class Specification {
    long leq;
    long geq;

    enum SignType {
    GEQ, GE, LEQ, LE;
    }

    Specification() {
        leq = 2000000000;
        geq = -2000000000;
    }

    void addSpec(String sign, long number, String answer) {
        
        SignType signType = stringToSign(sign);

        if (answer.equals("N")) {
            signType = invertSign(signType);
        }

        if (signType == SignType.LEQ) {
            if (leq > number) {
                leq = number;
            }
        } else if (signType == SignType.LE) {
            if (leq > number-1) {
                leq = number -1;
            }
        } else if (signType == SignType.GEQ) {
            if (geq < number) {
                geq = number;
            }
        } else if (signType == SignType.GE) {
            if (geq < number+1) {
                geq = number+1;
            }
        }

        // System.out.println("geq: "+geq);
        // System.out.println("leq: "+leq);

    }

    boolean canGuess() {
        return (geq <= leq);
    }

    long guess() {
        return (leq+geq)/2;
    }

    private SignType stringToSign(String sign) {
        if (sign.equals("<=")) {
            return SignType.LEQ;
        } else if (sign.equals("<")) {
            return SignType.LE;
        } else if (sign.equals(">=")) {
            return SignType.GEQ;
        } else if (sign.equals(">")) {
            return SignType.GE;
        } else {
            System.out.println("ERROR, sign: " + sign);
            // If called properly, this should not be reached
            return SignType.LEQ;
        }
    }

    private SignType invertSign(SignType sign) {
        if (sign == SignType.LEQ) {
            return SignType.GE;
        } else if (sign == SignType.LE) {
            return SignType.GEQ;
        } else if (sign == SignType.GEQ) {
            return SignType.LE;
        } else if (sign == SignType.GE) {
            return SignType.LEQ;
        } else {
            // Impossible case
            return sign;
        }
    }

}