有大佬帮忙看一下思路有啥问题吗？c++20分

#include <iostream>
#include <algorithm>
#include <cstring>

using namespace std;

int n;

int main()
{
	cin >> n;
	int sum = 1, m  = 1;
	for(int i = 2; i <= n / 2; i ++)
	{
		sum += (m + 1) * i;
		m ++;
	}	
	
	cout << sum << endl;
	 
	return 0;
}