#include <bits/stdc++.h>
using namespace std;
int n, m;
vector< vector<int> > grp;
vector<int> used;
void dfs ( int v, int p )
{
used[v] = 1;
for ( auto& to : grp[v] )
if ( to != p )
{
if ( used[to] )
{
cout << "NO\n";
exit(0);
}
dfs( to, v );
}
}
const int N = 1<<20;
pair<int,int> pre[N];
int main ()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cin >> n >> m;
grp.resize( n+1 );
for ( int i=0; i<m; i++ )
{
int u, v;
cin >> u >> v;
grp[u].push_back( v );
grp[v].push_back( u );
}
used.assign( n+1, 0 );
dfs( 1, -1 );
if ( n <= 20 )
{
queue<int> q;
q.push( (1<<n)-1 );
while ( q.size() && pre[0].second == 0 )
{
int v = q.front();
q.pop();
int x = 0;
for ( int i=0; i<n; i++ )
if ( (v>>i) & 1 )
for ( auto& to : grp[i+1] )
x |= 1 << (to-1);
for ( int i=0; i<n; i++ )
if ( pre[ x & (~(1<<i)) ].second == 0 )
{
pre[ x & (~(1<<i)) ] = { v, i+1 };
q.push( x & (~(1<<i)) );
if ( ( x & (~(1<<i)) ) == 0 )
break;
}
}
if ( pre[0].second == 0 )
{
cout << "NO\n";
return 0;
}
vector<int> ans;
int pos = 0;
while ( pos != (1<<n)-1 )
{
ans.push_back( pre[pos].second );
pos = pre[pos].first;
}
cout << "YES\n";
cout << ans.size() << '\n';
while ( ans.size() )
{
cout << ans.back() << ' ';
ans.pop_back();
}
return 0;
}
cout << "YES\n";
if ( n == 1 )
{
cout << "1 1";
return 0;
}
if ( n == 2 )
{
cout << "2 1 1";
return 0;
}
cout << 2*(n-2) << '\n';
for ( int i=2; i<n; i++ )
cout << i << ' ';
for ( int i=n-1; i>1; i-- )
cout << i << ' ';
return 0;
}
