import java.io.*;
import java.net.*;

class AddServer {
    public static void main( String[] args ) {
	try {
	    ServerSocket listen = new ServerSocket( 0 );
	    System.out.println("Server port is " + listen.getLocalPort() );

            /* handle one client at a time */
	    while ( true ) {
		Socket sock = listen.accept();

                /* data from client */
		DataInputStream din =
                    new DataInputStream( sock.getInputStream() );

                /* data to client */
		DataOutputStream dout =
                    new DataOutputStream( sock.getOutputStream() );

                for(;;) {
                    int sum = 0;
                    int sz = din.readInt();
                    if ( sz <= 0 ) break;
                    for( int i = 0 ; i < sz; i++ ) {
                        sum += din.readInt();
                    }
                    dout.writeInt( sum );
                    dout.flush();
                }
		System.out.println("Connection closed");
		sock.close(); // clean up required
                din.close();
                dout.close();
	    }
	}
	catch( IOException e ) {
	    System.out.println("error: " + e );
	}
    }
}