public class CheckLetterInString {
	public static void main(String[] args) {
		String str = "1a2b3c4d5e678f";
		int counter = 0;
		for (int k = 0; k < str.length(); k++) {
			if (Character.isLetter(str.charAt(k)))
				counter++;
		}
		System.out.println(counter + " letters.");
	}
}