#include <iostream>
#include <algorithm>
#include <vector>

using namespace std;

vector<int> ans;
vector<int> edge[5000], br[5000];
int timer = 0, tin[5000], up[5000], c[5000], bright[5001];
bool used[5000], used1[100000];

void dfs (int v, int s, int p = -1) {
    used[v] = 1;
    tin[v] = ++timer;
    up[v] = timer;
    for (int i = 0; i < edge[v].size(); i++) {
        int u = edge[v][i];
        if (u != p) {
            if (tin[u]) {
                up[v] = min(up[v], tin[u]);
            } else {
                dfs(u, i, v);
                up[v] = min(up[v], up[u]);
            }
        }
    }
    if (p != -1 && up[v] == tin[v]) {
        used1[br[p][s]] = 1;
    }
}

void dfs1(int v, int color) {
    used[v] = true;
    c[v] = color;
    for (int i = 0; i < edge[v].size(); i++) {
        int u = edge[v][i];
        if (used1[br[v][i]] && (c[u] != 0)) {
            bright[color] += 1;
            bright[c[u]] += 1;
        } else if (!used1[br[v][i]] && !used[u])
            dfs1(u, color);
    }
}

int main()
{
    int n, m, a, b;
    cin >> n >> m;
    for (int i = 0; i < m; i++) {
        cin >> a >> b;
        --a;
        --b;
        edge[a].push_back(b);
        edge[b].push_back(a);
        br[a].push_back(i);
        br[b].push_back(i);
    }
    for (int i = 0; i < n; i++)
        if (!used[i])
            dfs(i, 0);
    for (int i = 0; i < n; i++)
        used[i] = 0;
    for (int i = 0; i < n; i++)
        if (!used[i])
            dfs1(i, i + 1);
    int cnt = 0;
    for (int i = 1; i < n + 1; i++)
        cnt += (bright[i] == 1);
    cout << cnt / 2 + cnt % 2;
    /*for (int i = 0; i < n; i++)
        cout << c[i] << ' ';
    cout << endl;
    for (int i = 0; i < n + 1; i++)
        cout << bright[i] << ' ';
    cout << endl;*/
    return 0;
}