using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;

public class RemovedNumbers {
public static List<long[]> removNb(long n) {
            List<long[]> result = new List<long[]>();
            long sum = n * (n + 1) / 2;
            for (int j = 1; j <= n; j++) {
                long a = (sum - j) / (j + 1);
                if (a * j + a + j == sum && a < n) {
                    result.Add(new long[] { j, a });
                }
            }
            return result;
        }
}