#include <iostream>
#include <vector>

int main() {
    std::vector<int> values{3, 2, 1, 4, 1, 5};
    auto position = values.begin();
    while (position != values.end()) {
        if (*position % 2 == 0) {
            position = values.erase(position);
        } else {
            ++position;
        }
    }
    std::cout << values.size() << '\n';
    for (const auto& value : values) {
        std::cout << value << '\n';
    }
    return 0;
}