题解 | #尼科彻斯定理#

import java.util.Scanner;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {
    public static void main(String[] args) {
        BufferedReader reader = null;
        try {
            reader = new BufferedReader(new InputStreamReader(System.in));
            String s = reader.readLine();
            System.out.println(getSum(Integer.parseInt(s)));
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (reader != null) {
                try {
                    reader.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
    static String getSum(int n) {
        String str = String.valueOf(n * n - n + 1);
        for (int i = 1; i < n; i++) {
            str = str + "+" + String.valueOf(n * n - n + 1 + 2 * i);
        }
        return str;
    }
}