I have the following VB code:

____

For k = 1 To 4*n Step 2

iSum = iSum +1

Next k

For i = 1 To 2*n

For j = 1 To 3*n Step 3

iSum = iSum +1

Next j

iSum = iSum + 1

For m = 1 To 2*n

iSum = iSum + 1

iSum = iSum + 1

Next m

Next i

____

What is the complexity of this code in terms of Big Oh notation? I'm getting confused on what to look at. Is the notation going to be:

O(n^2)?

O(n^4)?

Why?

Thanks