import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.NoSuchElementException;
import java.util.Stack;

public class ExpressionEvaluator {
    interface Stack<E>{
        boolean isEmpty();
        boolean isFull();
        E peek();
        void clear();
        void push(E x);
        E pop();
    }

    static class SLLNode<E>{
        SLLNode<E> succ;
        E element;

        public SLLNode(E element, SLLNode<E> next) {
            this.succ = next;
            this.element = element;
        }
    }
    static class LinkedStack<E> implements Stack<E> {

        //Stekot e pretstaven na sledniot nacin: top e link do prviot jazol
        // na ednostrano-povrzanata lista koja sodrzi gi elementite na stekot .
        private SLLNode<E> top;

        public LinkedStack () {
            // Konstrukcija na nov, prazen stek.
            top = null;
        }

        public boolean isEmpty () {
            // Vrakja true ako i samo ako stekot e prazen.
            return (top == null);
        }

        @Override
        public boolean isFull() {
            return false;
        }

        public E peek () {
            // Go vrakja elementot na vrvot od stekot.
            if (top == null)
                throw new NoSuchElementException();
            return top.element;
        }

        public void clear () {
            // Go prazni stekot.
            top = null;
        }

        public void push (E x) {
            // Go dodava x na vrvot na stekot.
            top = new SLLNode<E>(x, top);
        }

        public E pop () {
            // Go otstranuva i vrakja elementot shto e na vrvot na stekot.
            if (top == null)
                throw new NoSuchElementException();
            E topElem = top.element;
            top = top.succ;
            return topElem;
        }

    }

    public static int evaluateExpression(String expression){
        // Vasiot kod tuka
        LinkedStack<Integer> stek=new LinkedStack<>();
        int i=0;
        while(i<expression.length()){
            if(expression.charAt(i)=='*'){
                i++;
                int broj=expression.charAt(i)-'0';
                if(i+1==expression.length()){
                    broj*=stek.pop();
                    stek.push(broj);
                    break;
                }
                while(Character.isDigit(expression.charAt(i+1))){
                    i++;
                    broj=broj*10 + expression.charAt(i)-'0';
                    if(i+1==expression.length()){
                        break;
                    }
                }
                broj*=stek.pop();
                stek.push(broj);
            }
            else if(Character.isDigit(expression.charAt(i))) {
                int broj=expression.charAt(i)-'0';
                if(i==expression.length()-1) {
                    stek.push(broj);
                    break;
                }
                while(Character.isDigit(expression.charAt(i+1))){
                    i++;
                    broj=broj*10 + expression.charAt(i)-'0';
                    if(i+1==expression.length()){
                        break;
                    }
                }
                stek.push(broj);
            }
            i++;
        }
        int rez=0;
        while(!stek.isEmpty()) rez+=stek.pop();
        return rez;
    }
    public static void main(String[] args) throws IOException {
        BufferedReader input=new BufferedReader(new InputStreamReader(System.in));
        System.out.println(evaluateExpression(input.readLine()));
    }

}