#include <bits/stdc++.h>
using namespace std;
int n, m, num;
struct xp {
  int u, v;
} ans[100000 + 5];
int gcd(int m1, int n1) {
  while (m1 > 0) {
    int c = n1 % m1;
    n1 = m1, m1 = c;
  }
  return n1;
}
void print() {
  printf("Possible\n");
  for (int i = 1; i <= num; i++) printf("%d %d\n", ans[i].u, ans[i].v);
}
int main() {
  scanf("%d%d", &n, &m);
  if (n - 1 > m) {
    printf("Impossible\n");
    return 0;
  }
  for (int i = 2; i <= n; i++) ans[++num].u = 1, ans[num].v = i;
  for (int i = 2; i <= n; i++)
    for (int j = i + 1; j <= n; j++)
      if (gcd(i, j) == 1) {
        if (num == m) {
          print();
          return 0;
        }
        ans[++num].u = i;
        ans[num].v = j;
      }
  if (num == m) {
    print();
    return 0;
  }
  printf("Impossible");
}
