using System;

public class Program

{

    public static void Main()

    {

        var length = int.Parse(Console.ReadLine()) ;

        var ar = new char[length];

        var c = 0;

        while (c < length)

        {

            var str = Console.ReadLine();

            c += str.Length - 1;

            for (int i = 0; i < str.Length; i++)

            {

                ar[c + i] = str[i];

            }

        }

        var counter = 0;

        var sum = 0;

        for (int i = 0; i < ar.Length; i ++)

        {

            if (ar[i] == '<')

            {

                sum += i - counter;

                counter++;

            }

        }

        Console.WriteLine(sum);

    }

}