#include <iostream>
#include <vector>
#include<fstream>
using namespace std;
#define MAX 100002
vector <int> graph[MAX];
int viz[MAX];
int nrc=0;

void dfs(int x)
{
    viz[x]=0;
    int i,lim=graph[x].size();
    for(i=0; i<lim; i++)
        if(graph[x][i]==1 && viz[i]==0)
            dfs(graph[x][i]);
}
int main()
{
    ifstream f("dfs.in");
    ofstream g("dfs.out");
    int N,M,x,y;
    f>>N>>M;
    int i;
    for(i=1; i<=M; i++)
    {
        f>>x>>y;
        graph[x].push_back(y);
        graph[y].push_back(x);
    }
    for (i=1; i<=N; i++)
    {
        if(viz[i]==0)
        {
            dfs(i);
            nrc++;
        }
    }
    g<<nrc<<endl;
    g.close();
    f.close();
    return 0;
}