/*
 * ReadClass
 * Burton Rosenberg
 * April 2004
 */

class ReadClass {


    // magic words to get a buffered reader from system.in
    static java.io.BufferedReader br = new java.io.BufferedReader(
            new java.io.InputStreamReader( System.in ) ) ;

    static int readInteger(String prompt) {
        if ( prompt!=null ) {
           System.out.print(prompt) ;
        }
        try {
            // get a line of text, parse it as an integer
            return Integer.parseInt(br.readLine()) ;
        }
        catch ( Exception e ) {
             return 0 ;  // hear no evil, see no evil approach to errors
        }
    }

    static int readPosInteger( String prompt, String errorPrompt ) {
      int i ;
      i = readInteger(prompt) ;
      while ( i<=0 ) {
         System.out.print(errorPrompt) ;
         i = readInteger(null) ;
      }
      return i ; 
    }


    static String readString( String prompt ) {
      if ( prompt!=null ) System.out.print(prompt) ;
      try {
         String s = br.readLine() ;
         if ( s.length()==0 ) return null ;
         return s ;
      }
      catch ( Exception e ) {
         return null ;
      }
    }
}