#include <bits/stdc++.h>
using namespace std;
int gcd(int a, int b) { return b == 0 ? a : gcd(b, a % b); }
int lcm(int a, int b) { return a * (b / gcd(a, b)); }
int cx[] = {-1, 1, 0, 0, 1, 1, -1, -1};
int cy[] = {0, 0, -1, 1, -1, 1, -1, 1};
bool is_possible(long long left, long long rigth) {
  if (left <= rigth) return true;
  return false;
}
int main() {
  ios::sync_with_stdio(0);
  int n;
  long long l = -2 * 1000000000, number, r = 2 * 1000000000;
  string option, answer;
  cin >> n;
  for (int i = (0), _b = ((n)-1); i <= _b; i++) {
    cin >> option >> number >> answer;
    if (option == ">=") {
      if (answer == "Y")
        l = max(l, number);
      else
        r = min(r, number - 1);
    } else if (option == "<=") {
      if (answer == "Y")
        r = min(r, number);
      else
        l = max(l, number + 1);
    } else if (option == ">") {
      if (answer == "Y")
        l = max(l, number + 1);
      else
        r = min(r, number);
    } else {
      if (answer == "Y")
        r = min(r, number - 1);
      else
        l = max(l, number);
    }
    if (!is_possible(l, r)) {
      cout << "Impossible" << endl;
      return 0;
    }
  }
  cout << r << endl;
  return 0;
}
