13245번 - Sum of digits 다국어

문제

It is easy to compute the sum of the numbers in the sequence from 0 to n with the formula n*(n+1)/2. That is: 0 + 1 + 2 + .... + n = n*(n+1)/2

This problem is a bit harder: what about the sum of the digits in the sequence [0, 1, ..., n]?

Write a program that computes the sum of the digits that can be found when counting from 0 to n.

For n = 15 we want to sum the digits that appear in the sequence [0, 1, 2, ..., 14, 15].

The result is: 1 +たす 2 +たす 3 +たす 4 +たす 5 +たす 6 +たす 7 +たす 8 +たす 9 +たす 1 +たす 0 +たす1 +たす 1 +たす 1 +たす 2 +たす 1 +たす 3 +たす 1 +たす 4 +たす 1 +たす 5 =わ 66

입력

A single line with an integer n (1 ≤ n ≤ 10¹⁶)

출력

A single line with the sum of digits in the sequence [0, 1, ..., n-1, n]

제한

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