#include <bits/stdc++.h>
using namespace std;
const int maxn = 100005;
vector<int> gcd_list[maxn];
int n, m, tot;
int gcd(int x, int y) {
  if (x < y) swap(x, y);
  while (y) {
    int c = x % y;
    x = y;
    y = c;
  }
  return x;
}
int main() {
  cin >> n >> m;
  if (m < n - 1) {
    cout << "Impossible" << endl;
    return 0;
  }
  for (int i = 1; i <= n; i++) {
    for (int j = i + 1; j <= n; j++) {
      if (gcd(i, j) == 1) {
        gcd_list[i].push_back(j);
        tot++;
      }
      if (tot > m) break;
    }
    if (tot > m) break;
  }
  if (tot < m) {
    cout << "Impossible" << endl;
    return 0;
  } else {
    cout << "Possible" << endl;
    for (int i = 1; i <= n; i++) {
      for (int j = 0; j < gcd_list[i].size() && m > 0; j++, m--) {
        cout << i << " " << gcd_list[i][j] << endl;
      }
    }
  }
  return 0;
}
