View Code of Problem 18

#include <stdio.h>
#include<iostream>
#include<cstdlib>
#include<cstdio>
#include<cstring>
#include<string>
#include<algorithm>
#include<vector>
#include<cmath>
using namespace std;	
	
int main() {
	int p[10000] = {};
	p[3] = 1;
	p[4] = 2;
	for (int i = 5; i < 10000; i++) {
		p[i] = p[i - 1] + (i + 1) / 2 - 1;
	}
	int n;
	while(cin >> n){
	cout << p[n] << endl;
	}
	return 0;
}