#include<cstdio>
#include<vector>
 
#define MAX_SIZE 100005
 
FILE *f=fopen("dfs.in","r");
FILE *g=fopen("dfs.out","w");
 
using namespace std;
 
vector<int> gr[MAX_SIZE];
int n,m;
int res;
bool used[MAX_SIZE];
 
void read ( void )
{
    fscanf(f,"%d%d",&n,&m);
     int x,y;
    for( int i(0); i < m ; ++i )
    {
        fscanf(f,"%d%d",&x,&y);
        gr[x].push_back(y);
        gr[y].push_back(x);
 
    }
    
}
void DFS(int node)
{    vector<int>::iterator it;
    used[node]=true;
    for( it=gr[node].begin();it!=gr[node].end(); it++)
        if(!used[*it])
            DFS(*it);
}
void solve( void )
{
  for(int i(1); i<=n ; ++i)
  {
      if(!used[i])
        {
            DFS(i);
            ++res;
        }
  }
 
}
void write( void )
{
    fprintf(g,"%d\n",res);
    fclose(f);
    fclose(g);
}
 
int main()
{
    read();
    solve();
    write();
    return 0;
}