#include <string>
#include <vector>

namespace numbers {
    complex eval(const std::vector<std::string> &args, const complex &z) {
        auto it = args.begin(), end = args.end();
        complex_stack stack;
        for (; it != end; ++it) {
            if ((*it)[0] >= 'a' && (*it)[0] <= 'z') {
                stack = stack << z;
                continue;
            }
            complex c1, c2;
            switch ((*it)[0]) {
                case '+':
                    c1 = +stack;
                    stack = ~stack;
                    c2 = +stack;
                    stack = ~stack;
                    stack = stack << (c1 + c2);
                    break;
                case '-':
                    c1 = +stack;
                    stack = ~stack;
                    c2 = +stack;
                    stack = ~stack;
                    stack = stack << (c1 - c2);
                    break;
                case '/':
                    c1 = +stack;
                    stack = ~stack;
                    c2 = +stack;
                    stack = ~stack;
                    stack = stack << (c1 / c2);
                    break;
                case '*':
                    c1 = +stack;
                    stack = ~stack;
                    c2 = +stack;
                    stack = ~stack;
                    stack = stack << (c1 * c2);
                    break;
                case '!':
                    c1 = +stack;
                    stack = stack << c1;
                    break;
                case ';':
                    stack = ~stack;
                    break;
                case '~':
                    c1 = +stack;
                    stack = ~stack;
                    stack = stack << (~c1);
                    break;
                case '#':
                    c1 = +stack;
                    stack = ~stack;
                    stack = stack << (-c1);
                    break;
                default:
                    stack = stack << complex(*it);
            }
        }
        return +stack;
    }
}