백준 1834번: 나머지와 몫이 같은 수

문제출처: https://www.acmicpc.net/problem/1834

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
 
public class Main {
    
    public static void main(String[] args) throws NumberFormatException, IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        long N = Long.parseLong(reader.readLine());
        long result = 0;
        int count = 1;
        
        while(count < N){
            result += N * count + count;
            count++;
        }
        
        System.out.println(result);
    }
}