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>
const int N = 2e5 + 1024;
const int M = 2e5 + 1024;
using namespace std;
int so(long long a) {
  int ret = 0;
  while (a) {
    ret += a % 10;
    a /= 10;
  }
  return ret;
}
int main() {
  long long n;
  cin >> n;
  long long nn = n;
  int cnt = 0;
  while (nn) {
    cnt++;
    nn /= 10;
  }
  cnt--;
  long long ans = 0;
  while (cnt) {
    cnt--;
    ans *= 10;
    ans += 9;
  }
  long long b = n - ans;
  long long out = so(b) + so(ans);
  cout << out;
  return 0;
}