using System;

namespace substract
{
    class Program
    {
        static void Main(string[] args)
        {
			Func<int,Func<int,int>>s=N=>P=>N-P++*(N+P/2);	
			Console.WriteLine(s(2)(3));		//-10
			Console.WriteLine(s(100)(5));	//-415
			Console.WriteLine(s(42)(0));		//42
			Console.WriteLine(s(0)(3));		//-6
			Console.WriteLine(s(0)(0));		//0
        }
    }
}