#include <iostream>

#include <vector>

#include <algorithm>

#include <map>

using namespace std;

vector< vector<int> > G;

vector<int> dfn, low, bridge;

int dep;

void dfs(int u, int par)

{

    dfn[u] = low[u] = ++dep;

    for (auto& v : G[u])

    {

        if (!dfn[v])

        {

            dfs(v, u);

            low[u] = min(low[u], low[v]);

        }

        else if (v != par) low[u] = min(low[u], low[v]);     

        if (low[v] > low[u]) bridge.emplace_back(v), bridge.emplace_back(u);

    }

}

int main()

{

    ios::sync_with_stdio(false);

    cin.tie(nullptr);

    cout.tie(nullptr);

    int n, m, a, b;

    while (cin >> n >> m)

    {

        // init

        G.assign(n + 1, vector<int>());

        dfn.assign(n + 1, 0);

        low.assign(n + 1, 0);

        bridge.clear();

        dep = 0;

        int con1 = 0, con0 = 0;

        // store data

        while (m--)

        {

            cin >> a >> b;

            G[a].emplace_back(b);

            G[b].emplace_back(a);

        }

        // find bridge connected component

        for (int i = 1; i <= n; ++i)

            if (!dfn[i])

            {

                size_t s = bridge.size();

                dfs(i, -1);

                if (s == bridge.size()) ++con0;

            }

        // solve

        if (bridge.size() == 0 && con0 == 1) cout << "0\n";

        else

        {

            map<int, int> m;

            for (int i = 1; i <= n; ++i) 

            {           

                m[low[i]] += 0;

                for (auto& v : G[i]) if (low[v] != low[i]) ++m[low[i]];

            }

            for (auto& [__, de] : m) if (de == 1) ++con1;

            cout << con0 + (con1 + 1) / 2 << "\n";           

        }        

    }

    return 0;

}