#include <iostream>
#include <fstream>

using namespace std;

int a[1001][1001], viz[1001], i, j, N, M, X, Y;

void DFS (int nod)
{
     viz[nod]=1;
     for (i=1; i<=N; i++)
          if((a[nod][i]==1)&&(viz[i]==0))
              DFS(i);
}

int main()
{
     int comp;
     ifstream f("dfs.in");
     ofstream g("dfs.out");
     f>>N>>M;
     for (int k=1; k<=M; k++)
           {f>>X>>Y;
            a[X][Y]=1;
            a[Y][X]=1;}
     comp=0;
     for (i=1; i<=N; i++) 
          viz[i]=0;
     for (i=1; i<=N; i++)    
          if (viz[i]==0)
             {DFS(i);
              comp++;}
      g<<comp;
      f.close();
      g.close();
      return 0;
}