cf Guess a number!

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).

Sample Input

Input

4>= 1 Y< 3 N<= -3 N> 55 N

Output

17

Input

2> 100 Y< -100 Y

Output

Impossible

#include <iostream>#include <stdio.h>#include <string.h>#include <cmath>using namespace std;const int INF=1e9+1;int main(){    int  n,now,num,ans;    int x1,x2,x3,x4;    char s1[5],s2[5];    while(cin>>n)    {        x1=-INF,x2=-INF;        x3=INF,x4=INF;        for(int i=1; i<=n; i++)        {            scanf("%s%d%s",s1,&num,s2);            int l1=strlen(s1);            int l2=strlen(s2);            int temp;            if((l1==2&&s1[0]=='>'&&s2[0]=='Y')||(l1==1&&s1[0]=='<'&&s2[0]=='N'))///>=Y,,<N            {                temp=num;                x1=max(temp,x1);            }            else if((l1==1&&s1[0]=='>'&&s2[0]=='Y')||(l1==2&&s1[0]=='<'&&s2[0]=='N'))///>Y,,<=N            {                temp=num+1;                x2=max(temp,x2);            }            else if((l1==2&&s1[0]=='<'&&s2[0]=='Y')||(l1==1&&s1[0]=='>'&&s2[0]=='N'))///<=Y,,>N            {                temp=num;                x3=min(temp,x3);            }            else if((l1==1&&s1[0]=='<'&&s2[0]=='Y')||(l1==2&&s1[0]=='>'&&s2[0]=='N'))///<Y,,>=N            {                temp=num-1;                x4=min(temp,x4);            }        }        int ans1=max(x1,x2);        int ans2=min(x3,x4);        if(ans1<=ans2)            cout<<ans1<<endl;        else            cout<<"Impossible"<<endl;    }    return 0;}