using System;
 
public class Test
{
	public static void Main()
	{
		for(var i = 0; i < 15; i++)
            Console.WriteLine ("#{0}: actual: {1}, estimated: {2}",
                i,
                GetActualCount(i),
                i * (i - 1) / 2);
	}
 
    static int GetActualCount(int n) {
    	var count = 0;
 
        for (int i = 0; i < n; i++)
            for (int j = 0; j < i; j++)    			
    				count++;
 
    	return count;
    }
}

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