#include <bits/stdc++.h>
using namespace std;
int gcd(int a, int b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}
int Euler(int n) {
  int res;
  res = n;
  for (int i = 2; i * i <= n; i++) {
    if (n % i == 0) {
      n /= i;
      res = res - res / i;
      while (n % i == 0) n /= i;
    }
  }
  if (n > 1) res = res - res / n;
  return res;
}
int main() {
  int n, m, cnt;
  int presum[605];
  presum[1] = 0;
  for (int i = 2; i <= 600; i++) presum[i] = presum[i - 1] + Euler(i);
  scanf("%d %d", &n, &m);
  if ((n <= 600 && m > presum[n]) || m < n - 1) {
    printf("Impossible\n");
    return 0;
  }
  printf("Possible\n");
  cnt = 0;
  for (int i = 1; i <= n - 1; i++) {
    for (int j = i + 1; j <= n; j++) {
      if (gcd(i, j) == 1) {
        printf("%d %d\n", i, j);
        cnt++;
        if (cnt == m) return 0;
      }
    }
  }
  return 0;
}
