#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int n, num, l, r;
  string str, res;
  cin >> n;
  l = 1e9;
  l = l * (-2);
  r = 1e9;
  r = r * (2);
  while (n--) {
    cin >> str >> num >> res;
    if (str == ">") {
      if (res == "Y")
        l = max(l, num + 1);
      else
        r = min(r, num);
    } else if (str == ">=") {
      if (res == "Y")
        l = max(l, num);
      else
        r = min(r, num - 1);
    } else if (str == "<") {
      if (res == "Y")
        r = min(r, num - 1);
      else
        l = max(l, num);
    } else {
      if (res == "Y")
        r = min(r, num);
      else
        l = max(l, num + 1);
    }
  }
  if (l > r)
    cout << "Impossible";
  else
    cout << l;
  return 0;
}
