you have to return the integer n such as
𝑛
3

(
𝑛
−
1
)
3
+
(
𝑛
−
2
)
3
+
.
.
.
+
1
3

𝑚
n
3
+(n−1)
3
+(n−2)
3
+...+1
3
=m if such a n exists or -1 if there is no such n.

OP has implemented the logic, it is basically summation of cubes of numbers from 1 to ... until it reaches or surpasses $m

I'm looking atht explination and just don't understand how it works. I'm going to have to study the wiki for this one as well.