#include<bits/stdc++.h>
using namespace std;
typedef long long ll;

ll n, x, c, v;

int main()
{
	scanf("%lld",&n);
	for(ll i=n;i;i/=10) {
		if(i/10 == 0) v = i%10;
		else {
			if(i%10 == 9) x++;
			c++;
		}
	}
	printf("%lld",v+c*9-(x!=c));
}

### Prompt

Please create a solution in CPP to the following problem:

Find the maximum possible sum of the digits (in base 10) of a positive integer not greater than N.

Constraints

* 1\leq N \leq 10^{16}
* N is an integer.

Input

Input is given from Standard Input in the following format:


N


Output

Print the maximum possible sum of the digits (in base 10) of a positive integer not greater than N.

Examples

Input

100


Output

18


Input

9995


Output

35


Input

3141592653589793


Output

137

### Response

```cpp
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;

ll n, x, c, v;

int main()
{
	scanf("%lld",&n);
	for(ll i=n;i;i/=10) {
		if(i/10 == 0) v = i%10;
		else {
			if(i%10 == 9) x++;
			c++;
		}
	}
	printf("%lld",v+c*9-(x!=c));
}

```