#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#pragma GCC optimize("unroll-loops")
using namespace std;
template <typename T>
void print(vector<T> s) {
  for (int i = 0; i < s.size(); i++) cout << s[i] << "";
  cout << endl;
}
int gcd(int a, int b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}
int main() {
  srand(time(NULL));
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int n, m;
  cin >> n >> m;
  if (n - 1 > m) {
    cout << "Impossible" << endl;
    return 0;
  }
  vector<pair<int, int> > s;
  for (int i = 1; i <= n; i++) {
    for (int j = i + 1; j <= n; j++) {
      if (gcd(i, j) == 1) {
        s.push_back(make_pair(i, j));
        m--;
        if (m == 0) break;
      }
    }
    if (m == 0) break;
  }
  if (m == 0) {
    cout << "Possible"
         << "\n";
    for (int i = 0; i < s.size(); i++)
      cout << s[i].first << " " << s[i].second << "\n";
  } else
    cout << "Impossible"
         << "\n";
  return 0;
}
