local fmt = require "fmt"

local function four_is_magic(n)
    local s = fmt.spell(n):upper(1)
    if n < 0 then s = s:replace("Minus", "Negative") end
    local t = s
    while n != 4 do
        n = #s
        s = fmt.spell(n)
        t ..= " is " ..  s .. ", " .. s
    end
    return t .. " is magic"
end

for {0, 4, 6, 11, 13, 75, 100, 337, -164,  9007199254740991} as n do
    print(four_is_magic(n))
    print()
end