Hatched Drawings

/* http://gosucoder.com/problem/P2 */
/* The plan is as follows:
 * 1. Track the (x,y) coordinates on each step (the starting point is (0,0))
 * 2. Calculate and remember the diagonal d where the coordinates are (the diagonal that goes through the current point and cuts the Y axis in (0,d))
 * 3. Two points found on the same diagonal indicate a starting and ending points of a line segment (increment count)
 * 3a. After finding a line segment, we need to remove the diagonal from our set, because another line segment can be found on the same diagonal (number of line segments = number of points / 2)
 * 3b. Some points have to be ignored: there's no line segment ending/starting in corners like '┘' (EN / SW) or '┌' (NE, WS), so we must keep track of what the next unit shift is
*/

using System;
using System.Collections.Generic;

public class Test
{
    public static void Main()
    {
    int n = int.Parse(Console.ReadLine());
        string a = Console.ReadLine();
        a = a + a[0];
        int x = 0, y = 0, count = 0;
        HashSet<int> diagonals = new HashSet<int>();

        for (int i = 0; i < n; i++)
        {
            switch (a[i])
            {
                case 'N': y++; if (a[i + 1] == 'E') continue; break;
                case 'S': y--; if (a[i + 1] == 'W') continue; break;
                case 'E': x++; if (a[i + 1] == 'N') continue; break;
                case 'W': x--; if (a[i + 1] == 'S') continue; break;
            }
            int d = y - x;
            if (diagonals.Contains(d))
                diagonals.Remove(d);
            else
            {
                diagonals.Add(d);
                count++;
            }
        }
    Console.WriteLine(count);
    }
}