#include <bits/stdc++.h>
using namespace std;
using ll = int64_t;
using ull = uint64_t;
using ld = long double;
int gcd(int x, int y) {
  if (y == 0) {
    return x;
  }
  return gcd(y, x % y);
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  cout.tie(nullptr);
  int n, m;
  cin >> n >> m;
  if (m < n - 1) {
    cout << "Impossible\n";
    return 0;
  }
  vector<pair<int, int> > ans;
  for (int i = 1; i + 1 <= n; i++) {
    ans.emplace_back(i, i + 1);
  }
  for (int i = 1; i <= n; i++) {
    if (ans.size() < m) {
      for (int j = i + 2; j <= n; j++) {
        if (ans.size() == m) {
          break;
        }
        if (gcd(i, j) == 1) {
          ans.emplace_back(i, j);
        }
      }
    }
  }
  if (ans.size() != m) {
    cout << "Impossible\n";
  } else {
    cout << "Possible\n";
    for (const auto& x : ans) {
      cout << x.first << " " << x.second << "\n";
    }
  }
}
