Problem: 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 ≤ a, b ≤ n, a + b = n and S(a) + S(b) is the largest possible among all such pairs.

Input

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

Output

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

Examples

Input

35


Output

17


Input

10000000000


Output

91

Note

In the first example, you can choose, for example, a = 17 and b = 18, so that S(17) + S(18) = 1 + 7 + 1 + 8 = 17. It can be shown that it is impossible to get a larger answer.

In the second test example, you can choose, for example, a = 5000000001 and b = 4999999999, with S(5000000001) + S(4999999999) = 91. It can be shown that it is impossible to get a larger answer.

Solution (in CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
int cnt(string s) {
  int sum = 0;
  for (int j = 0; j < s.size(); j++) {
    sum += s[j] - '0';
  }
  return sum;
}
int main(int argc, const char* argv[]) {
  long long N;
  cin >> N;
  int bestsum = 0;
  long long cand = 0;
  for (int i = 0; cand <= N; i++) {
    long long b = N - cand;
    ostringstream oss;
    oss << b;
    ostringstream oss2;
    oss2 << cand;
    int sum = cnt(oss.str() + oss2.str());
    bestsum = max(sum, bestsum);
    cand = cand * 10 + 9;
  }
  cout << bestsum << endl;
  return 0;
}