#include <bits/stdc++.h>
#include <cassert>
using namespace std;
#define all(v) v.begin(), v.end()
typedef long long ll;
const int NMAX = 3e5 + 5;
ll n, m, a, b, dfsn[NMAX], cnt[NMAX], x[NMAX], y[NMAX], t, ans, sum;
vector<int> adj[NMAX];
void dfs(int now, int bef) {
dfsn[now] = ++t;
int f = 1;
for (int nx : adj[now]) {
if (nx == bef) continue;
if (!dfsn[nx]) {
ll c = cnt[now];
dfs(nx, now);
cnt[now] += cnt[nx];
if (cnt[now] - c > 1) f = 0;
x[now] += x[nx]; y[now] += y[nx];
}
else if (dfsn[nx] < dfsn[now]) x[now]++, cnt[now]++, cnt[nx]--;
else y[bef]++;
}
if (!y[now] && !(sum - x[now]) && f) ans += now;
return;
}
int main(void) {
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> n >> m;
sum = m - (n - 1);
assert(sum > 0);
while (m--) {
cin >> a >> b;
adj[a].emplace_back(b);
adj[b].emplace_back(a);
}
dfs(1, 0);
cout << ans;
return 0;
}
