#include<iostream>
#include<cctype>
#include<string>
using namespace std;
int stack[100];
int top=-1;
void push(int ch) {
    top++;
    stack[top]=ch;
}
int pop () {
    int c = stack[top];
    top--;
    return c;
}
int result (int a,int b,char c) {
    int a1 = a;
    int b1 = b;
    switch(c) {
        case '+': return a1+b1;
        case '-': return a1-b1;
        case '*': return a1*b1;
        case '/': return a1/b1;
        case '%': return a1%b1;
    }
}
int main () {
    string s;
    cin >> s;
    for(int i=0;i<s.length();i++) {
        if(isdigit(s[i])) {

            push(s[i]-'0');
        }
        else {
           int a = pop();
           int b = pop();
           push(result(b,a,s[i]));
        }
    }
    cout << stack[top];
    return 0;
}