#include <iostream>
#include <vector>
#include <string>
#include <utility>
#include <cmath>
#include <algorithm>
#include <stack>
using namespace std;

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0), cout.tie(0);
    string instr; cin >> instr;
    vector <long int> v;
    //12+34+*5-
    for (int i = 0; i < instr.size(); i++)
    {
        if (instr[i] - '\0' >= 48 && instr[i] - '\0' <= 57)
            v.push_back(instr[i] - '\0' - 48);
        else if (instr[i] - '\0' == 43)
        {
            long long int a, b;
            a = v[v.size() - 1];
            b = v[v.size() - 2];
            v.erase(v.begin() + v.size() - 2);
            v.erase(v.begin() + v.size() -1 );
            v.push_back(a + b);
        }
        else if (instr[i] - '\0' == 45)
        {
            long long int a, b;
            a = v[v.size() - 1];
            b = v[v.size() - 2];
            v.erase(v.begin() + v.size() - 2);
            v.erase(v.begin() + v.size() - 1);
            v.push_back(b - a);
        }
        else if (instr[i] - '\0' == 42)
        {
            long long int a, b;
            a = v[v.size() - 1];
            b = v[v.size() - 2];
            v.erase(v.begin() + v.size() - 2);
            v.erase(v.begin() + v.size() - 1);
            v.push_back(a * b);
        }
        else if (instr[i] - '\0' == 47)
        {
            long long int a, b;
            a = v[v.size() - 1];
            b = v[v.size() - 2];
            v.erase(v.begin() + v.size() - 2);
            v.erase(v.begin() + v.size() - 1);
            v.push_back(b / a);
        }
    }
    cout << v[v.size() - 1];
    return 0;
}