Калькулятор/Жадный

// OK https://informatics.msk.ru/moodle/mod/statements/view3.php?chapterid=113440#1

# include <iostream>

size_t a_n(size_t n) {
    return n / 2;
}

size_t b_n(size_t n) {
    return (n + 1) / 2;
}

size_t c_n(size_t n) {
    if (n != 0) {
        return (n - 1) / 2;
    }
    return 0;
}

int main() {
    size_t n, a, b, c;
    std::cin >> n >> a >> b >> c;
    while (b-- > 0) {
        n = b_n(n);
    }
    while (a-- > 0) {
        n = a_n(n);
    }
    while (c-- > 0) {
        n = c_n(n);
    }
    std::cout << n;
    return 0;
}