#include <bits/stdc++.h>

using namespace std;

typedef long long LL;

inline LL read () {

    LL res =  ;

    int f () ;

    char ch = getchar ();

    while (!isdigit(ch)) {

        if (ch == '-') f = - ;

        ch = getchar();

    }

    while (isdigit(ch)) res = (res << ) + (res << ) + (ch ^ ),ch = getchar();

    return res * f ;

}

const int N = +;

int a[N] , nxt [N] , head[N] , dfn[N] , low[N] , cnt , k ;

bool cut[N] , bst[N] ;

inline void Add (int x ,int y) {

    a[++k] = y ; nxt[k] = head[x]; head[x] = k ; return ;

}

inline void tarjan (int u,int mr) {

    int rc = ;

    dfn[u] = low[u] = ++ cnt ;

    for ( register int p = head[u] ; p ; p = nxt[p] ) {

        int v = a[p] ;

        if (! dfn [v]) {

            tarjan ( v , mr ) ;

            low[u] = min ( low[u] , low[v] );

            if (low[v] >= dfn[u] and u != mr) cut[u]=true;

            if (u == mr) rc ++ ;

        }

        low[u] = min ( low[u] , dfn[v] ) ;

    }

    if (u == mr and rc >= ) cut[mr] = true;

}

signed main() {

    int n = read() ;

    int m = read() ;

    int ans =  ;

    for ( register int i =  ;i <= m ; i ++) {

        int x = read() ;

        int y = read() ;

        Add (x,y) ; Add (y,x) ;

    }

    for ( register int i =  ;i <= n ; i ++)

    if ( ! dfn[i] ) tarjan ( i , i ) ;

    for ( register int i =  ;i <= n ; i ++)

    if ( cut[i] ) ans ++ ;

    cout << ans << endl ;

    for ( register int i =  ;i <= n ; i ++)

    if ( cut[i] ) cout << i << ' ' ;

    return  ;

}