import sys, math
sys.setrecursionlimit(10**8)
sys.set_int_max_str_digits(0)

H, S = input().split()
H = int(H[-1])
S = int(S[-1])

if (H - S)%2 == 0: #偶奇が一致
    print('Possible')
else:
    print('Impossible')