import java.util.regex.Pattern;

/* package whatever; // don't place package name! */

/* The class name doesn't have to be Main, as long as the class is not public. */
class Main {
    public static void main(String[] args) throws java.lang.Exception {
		for(int i = 0; i < 500000; i++){
        isAlpha("abc123def456hig789klm000");
        isAlpha("abcdefghijklmnopqrstuvwxyz");}
        
//            	for(int i = 0; i < 5000000; i++){
//        isOnlyWordChars("abc123def456hig789klm000");
//        isOnlyWordChars("abcdefghijklmnopqrstuvwxyz");}
        
//            	for(int i = 0; i < 5000000; i++){
//        isAlpha("abc123def456hig789klm000");
//        isAlpha("abcdefghijklmnopqrstuvwxyz");}
	}

	private static boolean isOnlyWordChars(String s) {
		char[] chars = s.toCharArray();
		for (char c : chars) {
			if (!Character.isLetter(c)) {
				return false;
			}
		}
		return true;
	}

	private static boolean isAlpha(String str) {
		if (str == null) {
			return false;
		}
		int sz = str.length();
		for (int i = 0; i < sz; i++) {
			if (Character.isLetter(str.charAt(i)) == false) {
				return false;
			}
		}
		return true;
	}

	private static final Pattern sOnlyWordChars = Pattern.compile("\\w+");

	private static boolean isOnlyWordChars2(String s) {
		return sOnlyWordChars.matcher(s).matches();
	}

}