#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") or (cout << "Impossible");
return 0;
}
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