import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

    public static void main(String[] args) {
        /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution. */
        Scanner in=new Scanner(System.in);
        int size=in.nextInt();
        String hike=in.next();
        int height=0;
        int valleys=0;
        for(int i=0;i<size;i++){
            if(hike.charAt(i)=='D'){
                if(height==0){
                    valleys++;
                }    
                height--;
            }
            else{
                height++;
            }    
        }
        System.out.println(valleys);
    }
}