#include <bits/stdc++.h>
using namespace std;
int gcd(int x, int y) {
  if (y != 0)
    return gcd(y, x % y);
  else
    return x;
}
int main() {
  int n, m;
  scanf("%d %d", &n, &m);
  if (m < n - 1) {
    printf("Impossible");
    return 0;
  }
  int a;
  a = m;
  for (int i = 1; i <= n; i++) {
    for (int j = i + 1; j <= n; j++) {
      if (gcd(i, j) == 1) {
        a--;
        if (a == 0) break;
      }
    }
    if (a == 0) break;
  }
  if (a == 0) {
    printf("Possible\n");
    for (int i = 1; i <= n; i++) {
      for (int j = i + 1; j <= n; j++) {
        if (gcd(i, j) == 1) {
          printf("%d %d\n", i, j);
          m--;
          if (m == 0) break;
        }
      }
      if (m == 0) break;
    }
  } else
    printf("Impossible");
}
