import java.util.Scanner;

class Main{
	static int[][] I={{1,0},{0,1}};
	static int mod=1000;
	static int[][] pow(int[][] a,int x){
		if(x==1 || x==0) return a;
		else if(x%2==0) return pow(mul(a,a),x/2);
		else return mul(pow(mul(a,a),x/2),a);
	}
	static int[][] mul(int[][] a,int[][] b){
		int[][] res=new int[2][2];
		for(int i=0;i<2;i++){
			for(int j=0;j<2;j++){
				for(int k=0;k<2;k++){
					res[i][j]+=a[i][k]*b[k][j];
					res[i][j]%=mod;
				}
			}
		}
		return res;
	}
	public static void main(String[] args) {
		Scanner sc=new Scanner(System.in);
		while(sc.hasNext()){
			int n=sc.nextInt();
			int[][] a={{1,3},{1,1}};
			int[][] ans=pow(a,n);
			if(n==0) System.out.println(1);
			else System.out.println((2*ans[0][0]+(n%2==0 ? -1 : 0))%mod);
		}
	}
}