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

using namespace std;

const int Nmax = 100005;

int N, M, D[Nmax], nrCompCon;
vector<int> G[Nmax];

void read()
{
    ifstream f("dfs.in");
    f >> N >> M;
    for(int i = 0; i < M; i ++)
    {
        int x, y;
        f >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    f.close();
}

void DFS(int k)
{
    stack<int> S;
    D[k] = 0;
    S.push(k);
    while(!S.empty())
    {
        int Node = S.top();
        S.pop();
        for(int i = 0; i < G[Node].size(); i ++)
        {
            int Ngh = G[Node][i];
            if(D[Ngh] == -1)
            {
                D[Ngh] = D[Node] + 1;
                S.push(Ngh);
            }
        }
    }
}

void solve()
{
    for(int i = 1; i <= N; i ++)
    {
        D[i] = -1;
    }
    for(int i = 1; i <= N; i ++)
    {
        if(D[i] == -1)
        {
            DFS(i);
            nrCompCon++;

        }
    }
}

void print()
{
    ofstream g("dfs.out");
    g << nrCompCon;
    g.close();
}

int main()
{
    read();
    solve();
    print();
    return 0;
}