#include <iostream>

#include <string>

#include <vector>

using namespace std;

typedef long long int ll;

int main() {

string input;

int a, b;

vector<ll> op;

while (cin >> input) {

if (isdigit(input[0])||isdigit(input[1]))

op.push_back(stoi(input));

else {

b = op.back();

op.pop_back();

a = op.back();

op.pop_back();

if (input == "+")

op.push_back(a + b);

else if (input == "-")

op.push_back(a - b);

else if (input == "*")

op.push_back(a * b);

else if (input == "/")

op.push_back(a / b);

else if (input == "%")

op.push_back(a % b);

}

}

cout << op.back() << "\n";

return 0;

}