build on a pile of cubes.js

// Your task is to construct a building which will be a pile of n cubes. The cube at the bottom will have a volume of 
// �
// 3
// n 
// 3
//  , the cube above will have volume of 
// (
// �
// −
// 1
// )
// 3
// (n−1) 
// 3
//   and so on until the top which will have a volume of 
// 1
// 3
// 1 
// 3
//  .

// You are given the total volume m of the building. Being given m can you find the number n of cubes you will have to build?

// The parameter of the function findNb (find_nb, find-nb, findNb, ...) will be an integer m and you have to return the integer n such as n^3 + (n-1)^3 + (n-2)^3 + ... + 1^3 = m
// if such a n exists or -1 if there is no such n.

// Examples:
// findNb(1071225) --> 45

// findNb(91716553919377) --> -1

function findNb(m) {
    let n = 1
    let squareRoot = Math.sqrt(m)
    let factorial = 1
    while (factorial <= squareRoot) {
      factorial += n
      n++
    }
   return factorial == squareRoot + 1 ? n-1 : -1
 }