#265. High Accuracy

High Accuracy

No testdata at current.

Background

Special for beginners, ^_^

Description

Given two integers n and m, print the sum of n+(n+1)+(n+2)+...+(m2)+(m1)+mn+(n+1)+(n+2)+...+(m-2)+(m-1)+m .

Format

Input

Two integers n and m.

Output

One integer, the sum of n+(n+1)+(n+2)+...+(m2)+(m1)+mn+(n+1)+(n+2)+...+(m-2)+(m-1)+m .

Samples

1 10
55

Limitation

1s, 1024KiB for each test case.

1099999nm1099999-10^{99999} \leq n \leq m \leq 10^{99999}