using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;

class Solution {
    static void Main(String[] args) {
        /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution */
        var stepsNr = int.Parse(Console.ReadLine());
            var stepsArray = Console.ReadLine().Select(c => c == 'D' ? -1 : 1).ToList();
            var valeys = 0;
            var altitude = 0;
            var i = 0;
            while(i != stepsNr)
            {
                var step = stepsArray[i++];
                var tempValey = altitude;
                altitude += step;
                if (altitude < 0 && tempValey == 0)
                    valeys++;
            }
            Console.WriteLine(valeys);
    }
}