#include <bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define pb push_back
#define mp make_pair
typedef pair<int, int> ii;
const int mod = 1e9 + 7;
const int inf = 1e9;
int add(int x, int y) {
return (1ll * x + 1ll * y) % mod;
}
int del(int x, int y) {
return ((1ll * x - 1ll * y) % mod + mod) % mod;
}
int mul(int x, int y) {
return (1ll * x * 1ll * y) % mod;
}
const int N = 1e5 + 5;
int n, m, bad[N], good[N], badEdge, ans, parity[N], dist[N], low[N];
vector<int> graph[N];
bool vis[N];
int cnt;
map<ii, int> mymap;
void dfs(int u, int p) {
dist[u] = low[u] = ++cnt;
vis[u] = 1;
parity[u] = parity[p] ^ 1;
for(int i = 0; i < graph[u].size(); i++) {
int v = graph[u][i];
if(!vis[v]) {
dfs(v, u);
bad[u] += bad[v];
low[u] = min(low[u], low[v]);
}
else {
if(parity[v] == parity[u]) {
if(dist[v] < dist[u]) {
bad[v]--;
bad[u]++;
badEdge++;
}
}
else {
if(v == p && mymap[{u, v}] >= 2)
low[u] = min(low[u], dist[v]);
else if(v != p)
low[u] = min(low[u], dist[v]);
}
}
}
}
void bfs(int u, int p) {
vis[u] = 1;
if(u != 1) {
if(bad[u] == badEdge && low[u] == dist[u])
ans++;
}
for(int i = 0; i < graph[u].size(); i++) {
int v = graph[u][i];
if(v == p) continue;
if(!vis[v])
bfs(v, u);
}
}
int main() {
cin.tie(0), ios_base::sync_with_stdio(0);
cin >> n >> m;
for(int i = 1; i <= m; i++) {
int u, v;
cin >> u >> v;
graph[u].pb(v);
mymap[{u, v}]++;
mymap[{v, u}]++;
graph[v].pb(u);
}
for(int i = 1; i <= n; i++) {
if(!vis[i])
dfs(i, i);
}
if(badEdge == 1)
ans++;
memset(vis, 0, sizeof(vis));
for(int i = 1; i <= n; i++) {
if(!vis[i])
bfs(i, i);
}
cout << ans;
}
