#!/usr/bin/env python3
def solve(n, m):
    cur = set([ 1 ])
    for x in range(2, n+1):
        prv = cur
        cur = set()
        for y in prv:
            cur.add(+ x + y)
            cur.add(+ x - y)
            cur.add(- x + y)
        if 1 in prv:
            cur.add(x)
        if x >= 3:
            assert all(z in cur for z in range(x + 1))
    return m in cur
n, m = map(int, input().split())
print(['Impossible', 'Possible'][solve(n, m)])