Problem:
Score : 700 points

Problem Statement

Find the smallest possible sum of the digits in the decimal notation of a positive multiple of K.

Constraints

2 \leq K \leq 10^5

K is an integer.

Input

Input is given from Standard Input in the following format:

K

Output

Print the smallest possible sum of the digits in the decimal notation of a positive multiple of K.

Sample Input 1

6

Sample Output 1

3

12=6×2 yields the smallest sum.

Sample Input 2

41

Sample Output 2

5

11111=41×271 yields the smallest sum.

Sample Input 3

79992

Sample Output 3

36

Solution in C++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include<iostream>
using namespace std;

int digitsum(int n){
	int ans=0;
	while(n>0){
		ans+=n%10;
		n/=10;
	}
	return ans;
}
int main(){
	long long k;
	cin >> k;
	int ans=81;
	for(int i=2;i*k<1e9;i++){
		ans=min(ans,digitsum(k*i));
	}
	cout << ans << endl;
}