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

#define FOR(i, a, b) for(int i = (a); i < (b); i++)
#define RFOR(i, b, a) for(int i = (b) - 1; i >= (a); i--)
#define SZ(a) (int)a.size()
#define ALL(a) a.begin(), a.end()
#define PB push_back
#define MP make_pair
#define F first
#define S second

typedef long long LL;
typedef vector<int> VI;
typedef pair<int, int> PII;
typedef double db;

int main()
{
    ios::sync_with_stdio(0); 
    cin.tie(0);
	cout << fixed << setprecision(15);
	
	int n;
	cin >> n;
	int len = 0;
	LL pw = 1;
	while(pw <= n)
	{
		len++;
		pw *= 10;
	}
	pw /= 10;
	
	int x = (n / pw);
	
	int ans = 10 * (len - 1) + x - 1;
	
	if((10 * pw - 1) * x / 9 <= n)
		ans++;
		
	cout << ans << endl;
	
	
	
	
	
	
	return 0;
}