#include <bits/stdc++.h>
using namespace std;
int n, m;
int sum, num;
bool flag[100050];
int p[100050], ans[100050][2];
int gcd(int a, int b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}
int main() {
  scanf("%d%d", &n, &m);
  int cnt = 0;
  for (int i = 1; i <= n; i++) {
    for (int j = i + 1; j <= n; j++) {
      if (gcd(i, j) == 1) {
        ans[cnt][0] = i, ans[cnt++][1] = j;
        if (cnt >= m) break;
      }
    }
    if (cnt >= m) break;
  }
  if (cnt < m || m < n - 1)
    printf("Impossible\n");
  else {
    printf("Possible\n");
    for (int i = 0; i < cnt; i++) printf("%d %d\n", ans[i][0], ans[i][1]);
  }
  return 0;
}
