#include <bits/stdc++.h>
using namespace std;
int gcd(int a, int b) {
  if (a < b) return gcd(b, a);
  if (b == 0) return a;
  return gcd(b, a % b);
}
int main() {
  int n, m;
  cin >> n >> m;
  if (m < n - 1) {
    cout << "Impossible" << endl;
    return 0;
  }
  vector<pair<int, int> > ans;
  for (int i = 1; i <= n; i++) {
    for (int j = i + 1; j <= n; j++) {
      if (gcd(i, j) == 1) {
        ans.push_back(make_pair(i, j));
        if (ans.size() == m) {
          cout << "Possible" << endl;
          for (int k = 0; k < (int)ans.size(); k++) {
            cout << ans[k].first << " " << ans[k].second << endl;
          }
          return 0;
        }
      }
    }
  }
  cout << "Impossible" << endl;
  return 0;
}
