#include <bits/stdc++.h>
using namespace std;

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

int n,m,viz[100005],cnt;
vector<int> v[100005];

void citire()
{
    fin>>n>>m;
    int i,x,y;
    for(i=1; i<=m; i++)
    {
        fin>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
}

void BFS(int start)
{
    queue<int> q;
    q.push(start);
    viz[start]=1;

    while(!q.empty())
    {
        int nod=q.front();
        q.pop();

        for(int i=0; i<v[nod].size(); i++)
            if(!viz[v[nod][i]])
            {
                viz[v[nod][i]]=1;
                q.push(v[nod][i]);
            }
    }
}

int main()
{
    citire();

    int i;
    for(i=1; i<=n; i++)
        if(!viz[i])
        {
            cnt++;
            BFS(i);
        }

    fout<<cnt<<'\n';

    return 0;
}