#include <bits/stdc++.h>
#pragma warning(disable : 4996)
using namespace std;
const int MAXN = 1e5 + 10;
int phi[MAXN], prime[MAXN];
void getprime() {
  for (int i = 2; i < MAXN; i++) {
    if (!prime[i]) {
      prime[++prime[0]] = i;
      phi[i] = i - 1;
    }
    for (int j = 1; j <= prime[0] && prime[j] * i <= MAXN; j++) {
      prime[i * prime[j]] = 1;
      if (i % prime[j] == 0) {
        phi[i * prime[j]] = phi[i] * prime[j];
        break;
      } else
        phi[i * prime[j]] = phi[i] * (prime[j] - 1);
    }
  }
  for (int i = 2; i <= MAXN; i++) {
    phi[i] += phi[i - 1];
    if (phi[i] > MAXN) phi[i] = MAXN;
  }
}
int gcd(int a, int b) {
  while (b) {
    int t = b;
    b = a % b;
    a = t;
  }
  return a;
}
int main() {
  getprime();
  int n, m;
  scanf("%d%d", &n, &m);
  if (phi[n] >= m && m >= n - 1) {
    printf("Possible\n");
    for (int i = 1; i <= n && m; i++) {
      for (int j = i + 1; j <= n && m; j++) {
        if (gcd(i, j) == 1) {
          printf("%d %d\n", i, j);
          m--;
        }
      }
    }
  } else
    printf("Impossible\n");
  return 0;
}
