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

h = A*100+B*50-D*100

if D >= 10
    puts "Impossible"
else
    puts "Possible"
    s = 0
    c = 0
    B.times do |i|
        s += 50*(2**((c)/100))
        c += 1
    end
    A.times do |i|
        s += 100*(2**((c)/100))
        c += 1
    end
    p s
end