write a go solution for Description:
Calculate the value of the sum: n mod 1 + n mod 2 + n mod 3 + ... + n mod m. As the result can be very large, you should print the value modulo 109 + 7 (the remainder when divided by 109 + 7).

The modulo operator a mod b stands for the remainder after dividing a by b. For example 10 mod 3 = 1.

Input Format:
The only line contains two integers n, m (1 ≤ n, m ≤ 1013) — the parameters of the sum.

Output Format:
Print integer s — the value of the required sum modulo 109 + 7.

Note:
None. Output only the code with no comments, explanation, or additional text.