C++ :

#include<iostream>
using namespace std;
int main()
{
  int f[1001][2],n,i,x;
  cin>>n;
  f[1][1]=1;f[1][0]=9;                        
  for(i=2;i<=n;i++) 
   {   
      x=f[1][0];
      if(i==n)x--;
      f[i][0]=(f[i-1][0]*x+f[i-1][1])%12345;
      f[i][1]=(f[i-1][1]*x+f[i-1][0])%12345;   
   }
   cout<<f[n][0]; 
   return 0;
}

Java :

import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int a[] = new int[1001];
		int b[] = new int[1001];
		int i,n;
		n = sc.nextInt();
		a[1]=1;
		b[1]=8;
		for(i=2;i<=n;i++){
			a[i] = (a[i-1]*9+b[i-1])%12345;
			b[i] = (b[i-1]*9+a[i-1])%12345;
		}
		System.out.println(b[n]);		
		sc.close();
		
	}
}