双指针

import java.io.*;
import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        PrintWriter pw = new PrintWriter(System.out);

        String str = br.readLine();
        int left = str.length() - 1, right = str.length() - 1;
        while (left >= 0) {
            while (left >= 0 && Character.isLetter(str.charAt(left))) {
                left--;
            }
            pw.printf("%s ", str.substring(left + 1, right + 1));
            while (left >= 0 && !Character.isLetter(str.charAt(left))) {
                left--;
            }
            right = left;
        }
        pw.println();

        pw.flush();
        pw.close();
        br.close();
    }
}