题库练习 Maximum Sum of Digits
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A12098 | Maximum Sum of Digits

时间限制1s
内存限制256MB
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题目描述

You are given a positive integer $n$ .

Let $S(x)$ be sum of digits in base 10 representation of $x$ , for example, $S(123) = 1 + 2 + 3 = 6$ , $S(0) = 0$ .

Your task is to find two integers $a, b$ , such that $0 \leq a, b \leq n$ , $a + b = n$ and $S(a) + S(b)$ is the largest possible among all such pairs.

输入格式

The only line of input contains an integer $n$ $(1 \leq n \leq 10^{12})$ .

输出格式

Print largest $S(a) + S(b)$ among all pairs of integers $a, b$ , such that $0 \leq a, b \leq n$ and $a + b = n$ .

输入输出样例

输入 #1
35
输出 #1
17
输入 #2
10000000000
输出 #2
91
C++ 编辑器
输入
输出