import java.util.*;

class Main{
	public static void main(String args[]){
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		if(n == 0){
			System.out.println(0);
		}else{
			int num[] = {1,4,2,8,5,7};
			System.out.print("0.");
			int idx = 0;
			for(int i = 1; i <= n; i++){
				System.out.print(num[idx]);
				idx++;
				if(idx == 6){
					idx = 0;
				}
			}
			System.out.println();
		}
	}
}