#include <iostream>
#include "stack.h"

using namespace std;

int main()
{
    int n;
    cout << "n = ";
    cin >> n;

    stack *s = NULL;
    char* buf = new char[32];
    for (int i = 0; i < n; i++)
    {
        cin >> buf;
        if ('0' <= buf[0] && buf[0] <= '9')
        {
            int i = atoi(buf);
            push(s, i);
        }
        else 
        {
            switch (buf[0])
            {
                case '+': {
                    int o1 = pop(s);
                    int o2 = pop(s);
                    push(s, o2 + o1);
                } break;
                        
                case '-': {
                    int o1 = pop(s);
                    int o2 = pop(s);
                    push(s, o2 - o1);
                } break;

                case '*': {
                    int o1 = pop(s);
                    int o2 = pop(s);
                    push(s, o2 * o1);
                } break;
            }
        }
    }

    int result = pop(s);
    cout << "Result = " << result << endl;

    return 0;
}