Problem:
Score : 300 points

Problem Statement

Find the maximum possible sum of the digits (in base 10) of a positive integer not greater than N.

Constraints

1\leq N \leq 10^{16}

N is an integer.

Input

Input is given from Standard Input in the following format:

N

Output

Print the maximum possible sum of the digits (in base 10) of a positive integer not greater than N.

Sample Input 1

100

Sample Output 1

18

For example, the sum of the digits in 99 is 18, which turns out to be the maximum value.

Sample Input 2

9995

Sample Output 2

35

For example, the sum of the digits in 9989 is 35, which turns out to be the maximum value.

Sample Input 3

3141592653589793

Sample Output 3

137

Solution in C++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <algorithm>
#include <cmath>
#include <iostream>
#include <map>
#include <vector>

using namespace std;

int main() {
    long long int N;
    cin >> N;

    long long int tmp = N;
    int max;
    int keta = 0;
    while(tmp != 0) {
        tmp /= 10;
        keta++;
        if (tmp == 0) break;
        max = tmp;
    }

    // cout << keta << ":" << max << endl;

    long long int ans = 0;
    for (int i = 0; i < keta - 1; i++) {
        ans += 9;
    }
    ans += max - 1;
    cout << ans;
}