Problem:
Score : 300 points

Problem Statement

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.

Sample Input 1

100

Sample Output 1

18

For example, the sum of the digits in 99 is 18, which turns out to be the maximum value.

Sample Input 2

9995

Sample Output 2

35

For example, the sum of the digits in 9989 is 35, which turns out to be the maximum value.

Sample Input 3

3141592653589793

Sample Output 3

137

Solution in JavaScript (node.js v5.12) (judge verdict: Wrong Answer)

function Main(input){
	var N = input + "";
	var l = N.length;
	var lt = parseInt(N.substr(0,1));
	var rt = N.substr(1).match(/9/g);
	var ans;
	if(rt) rt = rt.length;
	else rt = -1;
	
	if(l === 1)ans = parseInt(N);
	else if(rt === l - 1) ans = (l - 1) * 9 + lt;
	else ans = (l - 1) * 9 + lt - 1;
	
	console.log(ans);
}

Main(require("fs").readFileSync("/dev/stdin", "utf8"));