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 JAVA):

Solution:
n = +readline();
if (n < 10){
    print(n);
} else {
    ar = (n+'').split('').map(Number);
    acc = 9;
    digit = 1;
    while (acc < n){
        acc *= 10;
        acc += 9;
        digit++;
    }
    if (acc === n){
        print(digit*9);
    } else {
        acc = ar[0]-1;
        digit--;
        while (digit-->0){
            acc *= 10;
            acc +=9;
        }
        sum = 0;
        ((n - acc)+'').split('').map(Number).forEach(x=>sum+=x);
        (acc+'').split('').map(Number).forEach(x=>sum+=x);
        print(sum);
    }
}