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

using namespace std;

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


const int NMAX=100005;

vector <int> graf[NMAX];
queue <int> q;

int n,m,v[NMAX],sol;

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

void bfs(int start)
{
    q.push(start);
    v[start]=1;
    while(!q.empty())
    {
        int nownod=q.front();
        q.pop();
        int nrnod=graf[nownod].size();
        for(int i=0;i<nrnod;i++)
        {
            int nextnod=graf[nownod][i];
            if(v[nextnod]==0)
            {
                v[nextnod]=1;
                q.push(nextnod);
            }
        }
    }
}

void solve()
{
    for(int i=1;i<=n;i++)
    {
        if(v[i]==0)
        {
            bfs(i);
            sol++;
        }
    }
}

void afisare()
{
    out<<sol;
}

int main()
{
    citire();
    solve();
    afisare();
    return 0;
}