#include <cmath> 
#include <iostream>
using namespace std;
 
int main() {
  int H, W, h, w;
  cin >> h >> w >> H >> W;
  int t = max(H, W);
  H = min(H, W);
  W = t;
  t = max(h, w);
  h = min(h, w);
  w = t;
  int d2 = w * w + h * h;
 (h <= H and w <= W or H * sqrt(d2 - W * W) + W * sqrt(d2 - H * H) <= w * w - h * h) and cout << "Possible";
  !(h <= H and w <= W or H * sqrt(d2 - W * W) + W * sqrt(d2 - H * H) <= w * w - h * h) and cout << "Impossible";
  return 0;
}

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