#include <bits/stdc++.h>
using namespace std;
struct pp {
  long long x, y;
};
const int base = 1000 * 1000 * 1000;
const int days[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
const int inf = (int)1e11;
const int mod = 1e6 + 3;
long long gcd(long long a, long long b) {
  while (b) {
    a %= b;
    swap(a, b);
  }
  return a;
}
long long binpow(long long a, long long n) {
  long long res = 1;
  while (n) {
    if (n & 1) res *= a, res %= mod;
    a *= a, a %= mod;
    n >>= 1;
  }
  return res % mod;
}
long long t, n, m, k, x, y, z, cnt, maxx = -inf, minn = inf, a[222222],
                                    c[222222], sum;
long long b[222222];
int main() {
  cin >> n >> m;
  if (m < n - 1 || m > (n - 1) * n / 2) {
    cout << "Impossible";
    return 0;
  }
  vector<pair<long long, long long> > v;
  for (long long i = 1; i <= n; i++) {
    for (long long j = i + 1; j <= n; j++) {
      if (gcd(i, j) == 1) {
        v.push_back(make_pair(i, j));
        cnt++;
        if (cnt == m) {
          cout << "Possible" << endl;
          for (auto i : v) cout << i.first << " " << i.second << endl;
          return 0;
        }
      }
    }
  }
  cout << "Impossible";
  return 0;
}
