import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
 
class A_JabberID {
	public static void main(String[] args) throws Exception {
		String str = new Scanner(System.in).nextLine();
		String r1 = "[\\w]{1,16}@([\\w\\.]{1,32})(/[\\w]{1,16}){0,1}";
		Matcher m = Pattern.compile(r1).matcher(str);
		if (m.matches() && m.group(1).matches("^[\\w]{1,16}(\\.[\\w]{1,16})*")) {
			System.out.println("YES");
		} else {
			System.out.println("NO");
		}
	}
}
 

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

bWlrZUBjb2RlZm9yY2VzLmNvbQo=

mike@codeforces.com