#include <bits/stdc++.h>
#define REP(i,n,N) for(int i=(n);i<(int)N;i++)
#define p(s) cout<<(s)<<endl
using namespace std;

int main(){
	string s;
	cin>>s;
	s+='?';
	int tmp=0,ans=0;
	int minus=!isdigit(s[0]);
	char c='-';
	REP(i,minus,s.size()){
		if(isdigit(s[i])){
			tmp*=10;
			tmp+=s[i]-'0';
		}else{
			if(minus) tmp=-tmp;
			if(c=='-') ans+=tmp;
			else ans-=tmp;
			c=s[i];
			tmp=0;
			if(!isdigit(s[i+1])){
				minus=true;
				i++;
			}
		}
	}
	p(ans);
	return 0;
}