#include <iostream>
#include <vector>
#include <queue>
#include <stack>
#include <fstream>
#include <map>

using namespace std;

ifstream fin("dfs.in");
ofstream fout("dfs.out");

vector<int> graf[100001];

int n, m, s;
map<int, bool> visited;
int dist[100001];

queue<pair<int, int>> q;

void bfs()
{
    q.push({s, 0});
    visited[s] = true;
    int cNode, pas;
    while (!q.empty())
    {
        cNode = q.front().first;
        pas = q.front().second + 1;
        dist[cNode] = pas - 1;
        for (int i = 0; i < graf[cNode].size(); i++)
        {
            if (!visited.count(graf[cNode][i]))
            {
                visited[graf[cNode][i]] = true;
                q.push({graf[cNode][i], pas});
            }
        }
        q.pop();
    }
}

stack<int> st;

void dfs(int nod)
{
    st.push(nod);
    visited[nod] = true;
    int cNode;
    while (!st.empty())
    {
        cNode = st.top();
        for (int i = 0; i < graf[cNode].size(); i++)
        {
            if (!visited.count(graf[cNode][i]))
            {
                visited[graf[cNode][i]] = true;
                st.push(graf[cNode][i]);
            }
        }
        st.pop();
    }
}

int main()
{
    fin >> n >> m; // >> s;
    int x, y;
    for (int i = 0; i < m; i++)
    {
        fin >> x >> y;
        graf[x].push_back(y);
        graf[y].push_back(x);
    }
    /*
    for (int i = 1; i <= n; i++)
    {
        dist[i] = -1;
    }
    bfs();
    for (int i = 1; i <= n; i++)
    {
        fout << dist[i] << ' ';
    }
    */
    int cnt = 0;
    for (int i = 1; i <= n; i++)
    {
        if (!visited.count(i))
        {
            cnt++;
            dfs(i);
        }
    }
    fout << cnt;
    return 0;
}