import java.util.Scanner;

public class Main {
    public static void main(String[] args) {

        Scanner scanner = new Scanner(System.in);
        String str = scanner.next();
        String emailMatcher="[a-zA-Z0-9]+@[a-zA-Z0-9]+\\.[a-zA-Z0-9]+";

        //write your code here......
	  // boolean matches(String regex):
      // matches() 方法用于检测字符串是否匹配给定的正则表达式
        if (str.matches(emailMatcher)){
            System.out.println("邮箱格式合法");
        } else {
            System.out.println("邮箱格式不合法");
        }

    }
}