#include <iostream>
#include <fstream>
#include <map>
#include <queue>
#define MAX 100001
using namespace std;
ifstream ci ("dfs.in");
ofstream co ("dfs.out");
vector <int>NOD[MAX];
map<pair<int,int>,bool>c;
queue <int>Q;
map<int,bool>viz;
int n,m;
int x,y;
void BFS (int x)
{
    viz[x]=true;
    Q.push(x);
    while (Q.size()>0)
    {
        int zz=Q.front();
        for (unsigned int i=0;i<NOD[zz].size();++i)
        {
            if (viz[NOD[zz][i]]==false)
            {
                viz[NOD[zz][i]]=true;
                Q.push(NOD[zz][i]);
            }
        }
        Q.pop();
    }
}
int main ()
{
    ci>>n>>m;
    while (m)
    {
        m--;
        ci>>x>>y;
        if (c[make_pair(x,y)]==false)
        {
            c[make_pair(x,y)]=true;
            c[make_pair(y,x)]=true;
            NOD[x].push_back(y);
            NOD[y].push_back(x);
        }
    }
    int temp=0;
    for  (int i=1;i<=n;++i)
    {
          if (viz[i]==false)
          {
              temp++;
              BFS(i);
          }
    }
    co<<temp;
    return 0;
}