#include <iostream>
#include <set>

using namespace std;

void bejar(int x, set<int>& megold, int fokszam[], int n, int a[][101]) {
    bool volt[10001] = {0};  // Track visited nodes
    volt[x] = 1;  // Mark the starting node as visited

    while (true) {
        int i = 1;  // Reset i to 1 each time we start searching for neighbors
        bool found = false;  // Flag to track if we find a valid unvisited neighbor

        // Search for the next unvisited neighbor
        while (i <= n) {
            if (a[x][i] == 1 && !volt[i] && fokszam[i] != 1) {  // Valid unvisited neighbor
                megold.insert(i);  // Add the neighbor to the result set
                volt[i] = 1;  // Mark the neighbor as visited
                x = i;  // Move to the newly found neighbor
                found = true;  // We found a valid neighbor
                break;  // Break out of the loop once we've found a neighbor
            }
            i++;  // Increment to check the next node
        }

        if (!found or fokszam[x] > 2) {
            break;  // Exit if no unvisited neighbor is found
        }
    }
}


int main() {
    int a[101][101] = {0}, n, m;
    cin >> n >> m;
    int x, y;
    for (int i = 0; i < m; i++) {
        cin >> x >> y;
        a[x][y] = 1;
        a[y][x] = 1;
    }

    int fokszam[101] = {0};
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= n; j++) {
            fokszam[i] += a[i][j];
        }
    }

    set<int> halmaz;
    for (int i = 1; i <= n; i++) {
        if (fokszam[i] == 1) {
            bejar(i, halmaz, fokszam, n, a);
        }
    }

    cout << halmaz.size() << endl;
    for (auto i : halmaz)
        cout << i << " ";
    return 0;
}