import java.io.*;
import java.util.*;
import antlr.*;
public class Main {
       public static void main(String[] args) throws Exception {
	          ExprLexer lexer = new ExprLexer(System.in);
		          ExprParser parser = new ExprParser(lexer);
			          int x = parser.expr();
				  System.out.println(x);
				      }
}