using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace ConsoleApplication20
{
class Program
{
static void Main(string[] args)
{ int say,tpl=0;
for (say = 2; say < 51; say+=3)
{
tpl += say;
}
Console.WriteLine(tpl);
Console.ReadLine();
}
}
}