View Code of Problem 18

#include<iostream>
#include<vector>
#include<algorithm>
#include<string>

using namespace std;


int main()
{
	int n;

	while (cin >> n) {

		if (n <= 2) {

			cout << 0 << endl;
			continue;
		}

		int sum = 0;
		int count = 0;
		for (int i = 1; i <= n; i++) {

			sum += count;

			if (i % 2 == 0)
				count++;
		}

		cout << sum << endl;
	}


}