#include <iostream>
#include <vector>

bool dfs(const std::vector<std::vector<bool> > &relationships, const bool &parity, std::vector<char> &is_visited, const int &human) {

    is_visited[human] = parity;
    for (int i = 0; i < relationships[human].size(); ++i) {
        if (relationships[human][i] == 0) {
            if (is_visited[human] == is_visited[i]) {
                return false;
            }
            else if (is_visited[i] == 2) {
                 if (!dfs(relationships, !parity, is_visited, i)) {
                     return false;
                 }
            }
        }
    }
    return true;

}
int main() {
    unsigned n, m;

    std::cin >> n >> m;
    std::vector<std::vector<bool> > relationships(n, std::vector<bool>(n, 0));

    for (int i = 0; i < m; ++i) {
        int first, second;
        std::cin >> first >> second;
        --first, --second;
        relationships[first][second] = 1;
        relationships[second][first] = 1;
    }

    for (int i = 0; i < n; ++i) {
        relationships[i][i]  = 1;
    }

    bool solution = true;
    std::vector<char> is_visited(n, 2);
    for (int i = 0; i < n; ++i) {
        if (is_visited[i] == 2) {
            solution = dfs(relationships, 0, is_visited, i);
        }
        if (!solution) {
            break;
        }
    }
    if (!solution) {
        std::cout << -1 << "\n";
        return 0;
    }
    int siz = 0;
    for (int i = 0; i < n; ++i) {
        if (!is_visited[i])
            ++siz;
    }
    std::cout << siz << "\n";
    for (int i = 0; i < n; ++i) {
        if (!is_visited[i]) {
            std::cout << i + 1 << " ";
        }
    }
    std::cout << '\n';
    for (int i = 0; i < n; ++i) {
        if (is_visited[i] == 1) {
            std::cout << i+1 << " ";
        }
    }
    return 0;
}