#include <iostream>
#include <vector>
using namespace std;

int n, m, a, b, ans = 0;
vector <vector <int>> g(1e5);
vector <int> p(1e5, 0);
vector <bool> fa(1e5, true);
vector <bool> szabad;

void dfs1(int x) {
    for (int i : g[x]) {
        if (i == p[x]) continue;
        if (p[i]) {
            a = x;
            if (fa[x]) while (a != p[i]) { fa[a] = false; a = p[a]; }
            continue;
        }
        p[i] = x;
        dfs1(i);
    }
}

void dfs2(int x) {
    fa[x] = false;
    int c = 0;
    for (int i : g[x]) {
        if (!fa[i]) continue;
        p[i] = x;
        dfs2(i);
        if (szabad[i]) c++;
    }
    if (!szabad[x]) return;
    if (c >= 2) {
        ans++;
        szabad[x] = false;
    }
    if (c == 1 && p[x] > 0 && szabad[p[x]]) {
        ans++;
        szabad[x] = false;
        szabad[p[x]] = false;
    }
}

int main()
{
    cin >> n >> m;
    for (int i = 0; i < m; i++) {
        cin >> a >> b;
        g[a].push_back(b);
        g[b].push_back(a);
    }
    p[1] = -1;
    dfs1(1);
    fill(p.begin(), p.end(), 0);
    szabad = fa;
    for (int i = 1; i <= n; i++) {
        if (!fa[i]) continue;
        p[i] = -1;
        dfs2(i);
    }
    cout << ans;
}