Link: https://leetcode.com/problems/divisible-and-non-divisible-sums-difference/
## Code

class Solution:
    def differenceOfSums(self, n: int, m: int) -> int:
        num2 = 0
        for i in range(1, n+1):
            if i%m == 0:
                num2 += i
        return ((1+n)*n)//2-2*num2