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 main() {
  std::ios::sync_with_stdio(false);
  ;
  long long n;
  std::cin >> n;
  long long tmp = n;
  int ct = 0, ls;
  while (tmp > 0) {
    ls = tmp % 10;
    tmp = tmp / 10;
    ct++;
  }
  long long gg = 0;
  gg = gg * 10 + (ls - 1);
  for (int i = 2; i <= ct; i++) {
    gg = gg * 10LL + 9LL;
  }
  long long no2 = n - gg;
  int s2 = 0;
  while (no2 > 0) {
    s2 += (no2 % 10);
    no2 /= 10;
  }
  std::cout << s2 + (9 * (ct - 1) + ls - 1) << endl;
  return 0;
}