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Leetcode
Easy
Math
Number Theory
Divisible And Non Divisible Sums Difference

Compute the difference between the sum of numbers from 1 to n that are not divisible by m and the sum of numbers that are divisible by m.

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Problem Statement

Problem

Given two integers n and m, consider all integers from 1 to n inclusive.

  • Let A be the sum of all numbers in this range that are not divisible by m.
  • Let B be the sum of all numbers in this range that are divisible by m.

Return A - B.

You should compute the result for the given pair (n, m).

Notes

  • A number x is divisible by m if x % m == 0.
  • The range always starts at 1 and ends at n.

Input Format

  • Two integers n and m.

Output Format

  • Return an integer representing A - B.

Constraints

  • 1 <= n
  • 1 <= m
  • Use the problem's input bounds as given by the platform when implementing.
Examples
Sample cases returned by the problem API.

Example 1

Input

n = 10, m = 3

Output

19

Explanation

Numbers not divisible by 3 are 1, 2, 4, 5, 7, 8, 10, whose sum is 37. Numbers divisible by 3 are 3, 6, 9, whose sum is 18. The difference is 37 - 18 = 19.

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