#include<iostream>
#include<fstream>
#include<vector>
using namespace std;

ifstream f("dfs.in");
ofstream g("dfs.out");

int N,M,S,i,viz[200005],x,y;
vector <int> v[200005];

void dfs(int nod)
{
    viz[nod]=1;
    for(int j=0;j<v[nod].size();j++)
        if(viz[v[nod][j]]==0)
            dfs(v[nod][j]);
}

int main()
{
    f>>N>>M;

    for(i=1;i<=M;i++)
    {
        f>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }

    for(i=1;i<=N;i++)
        if (viz[i]==0)
            {dfs(i); S++;}

    g<<S;

    f.close();
    g.close();
    return 0;
}