gets
e=gets.split.map &:to_i
d=[0,-1,0,1]
c=[]
until d.size>e.size
c<<x=e[-1]/d[-1]
d.size.times{|i|e[i+e.size-d.size]-=d[i]*x}
e.pop
end
e.pop while e!=[0]&&e[-1]==0
p e.size-1
puts e*' '