return {
  animals = function(heads, l)
    if 0 == heads and l == 0 then
      return {0,0}
    end
    hens = heads - (l-2*heads)/2
    cows = (l-2*heads)/2
    if (l <= 0 or heads <= 0) then
      return "No solutions"
    elseif (heads == 0 ) then
      return "No solutions"
    elseif ((cows < 0 or hens < 0) or (cows == 0 and hens == 0)) then
      return "No solutions"
    elseif (cows ~= math.floor(cows) or hens ~= math.floor(hens)) then
      return "No solutions"
    end
    return {hens, cows}
  end
}