Ito satta tato satta (seven there and seven here),
saṃsārāni (in rebirth process) catuddasa (fourteen)
OR, Seven there and seven here, in all fourteen rebirths.
Also, I think “rebirth” is a better word than “transmigration”. The latter is used more with reincarnation, a Hindu concept:
What Reincarnates? – Concept of a Lifestream