import java.io.*;
class myio{
	private DataInputStream in;
	public myio(){
		in = new DataInputStream(System.in);
		}
	public String rdstr(){
		String line = new String();
		try {
			line=in.readLine();
			return(line);
			} catch (Exception e) {
				e.printStackTrace();
			    return((String)null);
			    }
		}
	}