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

public class Validate {
	final static int MAXLEN = 100;

	String validRebus(String s) {
		if (!s.matches("^('*[a-z]*'*)( ('*[a-z]*'*))*$")) {
			return "s has invalid format";
		}
		StringTokenizer st = new StringTokenizer(s);
		while (st.hasMoreTokens()) {
			String t = st.nextToken();
			int nQ = 0, nO = 0;
			for (int i = 0; i < t.length(); i++) {
				if (t.charAt(i) == '\'') {
					nQ++;
				} else {
					nO++;
				}
			}
			if (nQ > nO) {
				return "Need to remove too many characters from the word";
			}
		}
		return null;
	}

	public void run() {
		StrictScanner in = new StrictScanner(System.in);
		String s = in.readLine();
		String check = validRebus(s);
		ensure(check == null, check);
		ensureLimits(s.length(), 1, MAXLEN, "length of s");
		in.nextLine();
		in.close();
	}

	public static void main(String[] args) {
		new Validate().run();
	}

	public class StrictScanner {
		private BufferedReader in;
		private String line = "";
		private int pos;
		private int lineNo;

		public StrictScanner(InputStream source) {
			in = new BufferedReader(new InputStreamReader(source));
			nextLine();
		}

		public void close() {
			ensure(line == null, "Extra data at the end of file");
			try {
				in.close();
			} catch (IOException e) {
				throw new AssertionError("Failed to close with " + e);
			}
		}

		public void nextLine() {
			ensure(line != null, "EOF");
			ensure(pos == line.length(), "Extra characters on line " + lineNo);
			try {
				line = in.readLine();
			} catch (IOException e) {
				throw new AssertionError("Failed to read line with " + e);
			}
			pos = 0;
			lineNo++;
		}

		public String readLine() {
			ensure(line != null, "EOF");
			ensure(line.length() > 0, "Empty line " + lineNo);
			if (pos == 0)
				ensure(line.charAt(0) > ' ', "Line " + lineNo
						+ " starts with whitespace");
			else {
				ensure(pos < line.length(), "Line " + lineNo + " is over");
				ensure(line.charAt(pos) == ' ', "Wrong whitespace on line "
						+ lineNo);
				pos++;
				ensure(pos < line.length(), "Line " + lineNo + " is over");
				ensure(line.charAt(0) > ' ', "Line " + lineNo
						+ " has double whitespace");
			}
			pos = line.length();
			ensure(line.charAt(line.length() - 1) != ' ', "Line " + lineNo
					+ " ends with whitespace");
			return line;
		}

		public String next() {
			ensure(line != null, "EOF");
			ensure(line.length() > 0, "Empty line " + lineNo);
			if (pos == 0)
				ensure(line.charAt(0) > ' ', "Line " + lineNo
						+ " starts with whitespace");
			else {
				ensure(pos < line.length(), "Line " + lineNo + " is over");
				ensure(line.charAt(pos) == ' ', "Wrong whitespace on line "
						+ lineNo);
				pos++;
				ensure(pos < line.length(), "Line " + lineNo + " is over");
				ensure(line.charAt(0) > ' ', "Line " + lineNo
						+ " has double whitespace");
			}
			StringBuilder sb = new StringBuilder();
			while (pos < line.length() && line.charAt(pos) > ' ')
				sb.append(line.charAt(pos++));
			return sb.toString();
		}

		public int nextInt() {
			String s = next();
			ensure(s.length() == 1 || s.charAt(0) != '0',
					"Extra leading zero in number " + s + " on line " + lineNo);
			ensure(s.charAt(0) != '+', "Extra leading '+' in number " + s
					+ " on line " + lineNo);
			try {
				return Integer.parseInt(s);
			} catch (NumberFormatException e) {
				throw new AssertionError("Malformed number " + s + " on line "
						+ lineNo);
			}
		}

		public long nextLong() {
			String s = next();
			ensure(s.length() == 1 || s.charAt(0) != '0',
					"Extra leading zero in number " + s + " on line " + lineNo);
			ensure(s.charAt(0) != '+', "Extra leading '+' in number " + s
					+ " on line " + lineNo);
			try {
				return Long.parseLong(s);
			} catch (NumberFormatException e) {
				throw new AssertionError("Malformed number " + s + " on line "
						+ lineNo);
			}
		}

		public double nextDouble() {
			String s = next();
			ensure(s.length() == 1 || s.startsWith("0.") || s.charAt(0) != '0',
					"Extra leading zero in number " + s + " on line " + lineNo);
			ensure(s.charAt(0) != '+', "Extra leading '+' in number " + s
					+ " on line " + lineNo);
			// check on three digit
			String[] ss = s.split(".");
			if (ss.length == 2) {
				ensure(ss[1].length() <= 3,
						"There is more than three digit after point");
			}
			// --------------------
			try {
				return Double.parseDouble(s);
			} catch (NumberFormatException e) {
				throw new AssertionError("Malformed number " + s + " on line "
						+ lineNo);
			}
		}
	}

	void ensure(boolean b, String message) {
		if (!b) {
			throw new AssertionError(message);
		}
	}

	void ensureLimits(long n, long from, long to, String name) {
		ensure(from <= n && n <= to, name + " must be from " + from + " to "
				+ to);
	}

}