import java.io.IOException;
import java.io.InputStream;

public class Tool {
	public static void main(String[] args) throws IOException {
		InputStream in = System.in;
		String output = new Tool().exec(in);
		System.out.print(output);
	}

	public String exec(InputStream in) throws IOException {
		Lexer lex = new Lexer(in);
		Parser parser = new Parser(lex);
		String output = parser.prog();
		return output;
	}
}