#include <bits/stdc++.h>
using namespace std;
int n, m, ans;
struct QwQ {
  int x, y;
} vis[100003];
int exgcd(int a, int b) {
  if (b == 0)
    return a;
  else
    return exgcd(b, a % b);
}
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 (i != j && exgcd(i, j) == 1) {
        ans++;
        vis[ans].x = i;
        vis[ans].y = j;
      }
      if (ans == m) break;
    }
    if (ans == m) break;
  }
  if (ans == m) {
    cout << "Possible" << endl;
    for (int i = 1; i <= m; i++) {
      cout << vis[i].x << " " << vis[i].y << endl;
    }
  } else {
    cout << "Impossible" << endl;
  }
  return 0;
}
