BAEKJOON_1541

import java.io.*;
import java.util.Arrays;
import java.util.StringTokenizer;


public class Main {

    static int ans = Integer.MAX_VALUE;

    public static void main(String[] args) throws IOException {

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));

        StringTokenizer st = new StringTokenizer(br.readLine(),"-");

        while(st.hasMoreTokens()){
            int temp=0;

            StringTokenizer st2 = new StringTokenizer(st.nextToken(),"+");

            while(st2.hasMoreTokens()){
                temp +=Integer.parseInt(st2.nextToken());
            }

            if(ans ==Integer.MAX_VALUE){
                ans = temp;
            }else{
                ans -=temp;
            }
        }

        bw.write(ans+"\n");
        bw.flush();
        bw.close();


    }
}