u/Mama_Miia02

Building a Jeleva deak and had a question,

In her text it says "each player exiles the top X cards of their library, where X is the amount of mana spent to cast Jeleva"

Now if i were to cast a spell to make a copy of jeleva, so that i could trigger the ETB effects, say with [[Echocasting Symposium]] would I exile cards equal to here CMC or would I Exile Cards equal to the spell used to copy?