import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        int len = Integer.valueOf(input.nextLine());
        String s = input.nextLine();
        boolean isBig = false;
        int count = 0;
        for (int i=0; i < s.length(); i++ ){
            if (isBig) {
                if (Character.isUpperCase(s.charAt(i)))
                    continue;
                else {
                    count++;
                    if (i + 1 < s.length() && Character.isLowerCase(s.charAt(i + 1)))
                        isBig = false;
                }
            }
            else {
                if (Character.isLowerCase(s.charAt(i)))
                    continue;
                else {
                    count++;
                    if (i+1<s.length()&&Character.isUpperCase(s.charAt(i+1)))
                        isBig=true;
                }
            }

        }
        count += len;
        System.out.println(count);

    }

}