import java.util.Scanner;

public class Main {
	 
    /**
     * @param args
     */
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int a = sc.nextInt();
		int g = a%10;
		int s = a/10;
		double sum = (double)s/g;
		System.out.println(String.format("%.1f", sum));
		
	}
	public static void printArr(int [] a){
		for (int i = 0 ;i<= a.length - 1 ;i++) {
			System.out.print( a[i] + " ");
		}
	}
}
/**************************************************************
	Problem: 1607
	User: admin
	Language: Java
	Result: Accepted
	Time:795 ms
	Memory:40612 kb
****************************************************************/