Y NOT

Why is there no letter Y in the Greek alphabet? Is that a fact? Some words would not be intact, Or be understood, Only the Greeks would. How would the Greeks spell spy? What letter would suffice, When the letter Y is needed. Has it been superseded? It never existed or was blacklisted, That is not known, Or clearly shown. How will a Greek super sleuth, Be able to spy? Without a Y in their E.E They may never know why, And their profession will DIE.