A, B, C, D = gets.split.map(&:to_i)

if D >= 10
  puts 'Impossible'
  exit
end

combo = 0
score = 0

(A + B).times do |i|
  bonus = combo / 100
  if i < B
    score += 50 * 2.pow(bonus)
  else
    score += 100 * 2.pow(bonus)
  end
  combo += 1
end

puts 'Possible'
puts score