import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;


public class Solution {
    final static BufferedReader READER;
    final static PrintWriter WRITER;
    static{
        READER = new BufferedReader(new InputStreamReader(System.in));
        WRITER = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)));
    }
    
    public static void main(String[] args) {
        try {
            READER.readLine();
            WRITER.println(getNoOfValleys());
            WRITER.flush();
        } catch (IOException ex) {
            
        }
        finally{
            try{
                READER.close();
                WRITER.close();
            }
            catch(IOException ioEx){
                
            }
        }
    }

    private static int getNoOfValleys() throws IOException {
        int noOfValleys = 0;
        int depth = 0;
        boolean inValley = false;
        String steps = READER.readLine();
        char[] arr = steps.toCharArray();
        for(char c : arr){
            if(c == 'U'){
                depth++;
            }
            else{
                depth--;
            }
            if (depth < 0 && !inValley){
                inValley = true;                
            }
            else if (depth >= 0 && inValley){
                noOfValleys++;
                inValley = false;
            }
        }
        return noOfValleys;
                
    }
}