N1193 - 분수찾기

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int level = (int) Math.ceil((-1 + Math.sqrt(1 + 8 * n)) / 2);
        int a = n - (level - 1) * level / 2;
        int b = level + 1 - a;

        if (level % 2 == 0) {
            System.out.println(a + "/" + b);
        } else {
            System.out.println(b + "/" + a);
        }
    }
}