#include <bits/stdc++.h>
using namespace std;
int u[100005], v[100005], pool;
int gcd(int a, int b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}
int main() {
  int n, m;
  cin >> n >> m;
  if (m < n - 1) {
    cout << "Impossible";
    return 0;
  }
  for (int i = 1; i <= n; i++) {
    for (int j = i + 1; j <= n; j++) {
      if (pool == m) break;
      if (gcd(j, i) == 1) {
        u[++pool] = i;
        v[pool] = j;
      }
    }
    if (pool == m) break;
  }
  if (pool == m) {
    cout << "Possible" << endl;
    for (int i = 1; i <= pool; i++) cout << u[i] << " " << v[i] << endl;
  } else
    cout << "Impossible";
  return 0;
}
