import java.util.*;

public class Solution {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        String s = scan.nextLine();
        String[] sArr = s.split("[\\s+!,?._'@]");
        System.out.println(sArr.length);
        for (int i = 0; i < sArr.length; i++) {
            System.out.println(i + " <-> " + sArr[i]);
        }
        scan.close();
    }
}