from itertools import permutations

def possible(parts):
    for perm in permutations(parts):
        if all(perm[i] <= perm[i+1] for i in range(len(perm)-1)):
            return True, perm
    return False, None

t = int(input())
for i in range(1, t+1):
    p = int(input())
    parts = input().split()
    poss, perm = possible(parts)
    if poss:
        print(f"Case #{i}: POSSIBLE")
        print(" ".join(perm))
    else:
        print(f"Case #{i}: IMPOSSIBLE")