#include <iostream>
#include <fstream>
#include <queue>
#define Nmax 1000010
using namespace std;
ifstream fin("dfs.in");
ofstream gout("dfs.out");
int n,m,x,y, viz[Nmax],nr;
vector <int> G[Nmax];
queue <int> Q;
void citire()
{
    fin>>n>>m;
    for(int i=0;i<m;i++)
    {
        fin>>x>>y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
}
void bfs(int v)
{
    Q.push(v);
    viz[v]=1;
    while(!Q.empty())
    {
        int x=Q.front();
        Q.pop();
        for(vector <int> :: iterator it=G[x].begin();it!=G[x].end();++it)
            if(!viz[*it])
            {
                Q.push(*it);
                viz[*it]=1;
            }
    }
}
int numarare()
{
    int nr=0;
    for(int i=1;i<=n;i++)
        if(viz[i]==0)
            {
                bfs(i);
                nr++;
            }
    return nr;
}
int main()
{
    citire();
    gout<<numarare();
    return 0;
}