def arrayConversion(a)
    sum = ->(x){x.each_slice(2).to_a.map{|x,y| x+y}}
    mul = ->(x){ x.each_slice(2).to_a.map{|x,y| x*y}}
    odd = true
    while a.size != 1 do
        a = sum.(a) if odd
        a = mul.(a) unless odd
        odd ? odd = false : odd = true
    end
    a[0]
end