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;
struct mone {
  int value = -1;
};
const int N = 2e5 + 5;
bool comp(int x, int y) { return x > y; }
long long int sod(long long int n) {
  long long int ans = 0;
  while (n) ans += (n % 10), n /= 10;
  return ans;
}
long long int nod(long long int n) {
  long long int c = 0;
  while (n) c++, n /= 10;
  return c;
}
void solve() {
  long long int n;
  cin >> n;
  long long int temp = 0, t = 1;
  long long int k = n;
  while (n) {
    if (n / 10 == 0)
      temp += t * (n % 10 - 1);
    else
      temp += 9 * t;
    t *= 10;
    n /= 10;
  }
  cout << sod(temp) + sod(k - temp) << endl;
}
int32_t main() {
  ios::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  int t = 1;
  while (t--) {
    solve();
  }
}