#include <bits/stdc++.h>
using namespace std;
int ans[100200][2];
int gcd(int a, int b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}
int main() {
  int n, m;
  scanf("%d%d", &n, &m);
  if (m < n - 1) {
    printf("Impossible");
    return 0;
  }
  int cnt = 0;
  for (int i = 2; i <= n; i++) ans[cnt][0] = 1, ans[cnt++][1] = i;
  for (int i = 2; i <= n; i++) {
    if (cnt >= m) break;
    for (int j = i + 1; j <= n; j++) {
      if (cnt >= m) break;
      if (gcd(j, i) == 1) ans[cnt][0] = i, ans[cnt++][1] = j;
    }
  }
  if (cnt >= m)
    printf("Possible\n");
  else {
    printf("Impossible");
    return 0;
  }
  for (int i = 0; i < m; i++) printf("%d %d\n", ans[i][0], ans[i][1]);
  return 0;
}
