How to calculate the basic operation of this algorithm?

SumCubes (n)
// Given a positive integer n, return the sum of the cubes 1 ^ 3, 2 ^ 3 …. n ^ 3

    if n = 1
return 1
plus
return sumcubes (n-1) + (n * n * n)

How can I determine the basic operation? Does the basic operation mean something that is called many times, as sumcubes (n-1)?