n=int(input())
if n%2:print(0)
else:
d=n//2
if d%2:print(d//2)
else:print(d//2-1)#include<bits/stdc++.h>
using namespace std;
int main()
{
long long int n;
cin>>n;
if(n%2!=0){
cout<<0;
return 0;
}
if(n%2==0){
int a=n/2;
if(a%2==0){
a=(a/2)-1;
}
else{
a=a/2;
}
cout<<a;
}
return 0;
} 1302. Deepest Leaves Sum | 1209. Remove All Adjacent Duplicates in String II |
994. Rotting Oranges | 983. Minimum Cost For Tickets |
973. K Closest Points to Origin | 969. Pancake Sorting |
967. Numbers With Same Consecutive Differences | 957. Prison Cells After N Days |
946. Validate Stack Sequences | 921. Minimum Add to Make Parentheses Valid |
881. Boats to Save People | 497. Random Point in Non-overlapping Rectangles |
528. Random Pick with Weight | 470. Implement Rand10() Using Rand7() |
866. Prime Palindrome | 1516A - Tit for Tat |
622. Design Circular Queue | 814. Binary Tree Pruning |
791. Custom Sort String | 787. Cheapest Flights Within K Stops |
779. K-th Symbol in Grammar | 701. Insert into a Binary Search Tree |
429. N-ary Tree Level Order Traversal | 739. Daily Temperatures |
647. Palindromic Substrings | 583. Delete Operation for Two Strings |
518. Coin Change 2 | 516. Longest Palindromic Subsequence |
468. Validate IP Address | 450. Delete Node in a BST |