文件目录

#include <bits/stdc++.h>
using namespace std;
string s, num = "";
stack<long long> n;
long long a, b;
long long js(long long a, long long b, char c)
{
    switch (c)
    {
    case '+':
        return a + b;
    case '-':
        return a - b;
    case '*':
        return a * b;
    case '/':
        return a / b;
    }
}
int main()
{
    getline(cin, s);
    for (int i = 0; s[i] != '@'; i++)
    {
        if (s[i] >= '0' && s[i] <= '9')
            num += s[i];
        else if (s[i] == ' ')
        {
            n.push(stol(num));
            num = "";
        }
        else
        {
            b = n.top();
            n.pop();
            a = n.top();
            n.pop();
            n.push(js(a, b, s[i]));
        }
    }
    cout << n.top();
    return 0;
}