import java.io.InputStreamReader;
import java.io.BufferedReader;

public class Solution {
    public static void main(String[] args) throws Exception {
        BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));

        String s = bf.readLine();
        int ss = Integer.parseInt(s);
        //System.out.println(ss);
        System.out.println(getFeetFromInches(ss));


    }

    public static int getFeetFromInches(int inches) {
        //write your code here
        int feet = (1/12) * inches;
        return feet;
    }
}