#include <iostream>
#include <vector>
#include <algorithm>
#include <numeric>
#include <random>

using namespace std;

random_device rd;
mt19937 g(rd());

void remove(vector<int> &a) {
    for (int i = 0; i < a.size(); ++i) {
        if (a[i] & 1) {
            a.erase(a.begin() + i);
            --i;
        }
    }
}

void print(vector<int> &a) {
    for (auto el : a) {
        cout << el << " ";
    }
}

int no_in_vector(int x) {
    return x;
}

int main() {
    const int n = 50;
    vector<int> a(n);
    int x = rd() % (n + 1);
    iota(a.begin(), a.end(), 0);
    for (int i = x; i < n; ++i) ++a[i];
    shuffle(a.begin(), a.end(), g);
    cout << no_in_vector(x) << '\n';
    remove(a);
    print(a);
    return 0;
}