#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);
    for(int i(0); i <= m; ++i)
    {
        int x,y;
        fscanf(f,"%d%d",&x,&y);
        gr[x].push_back(y);
        gr[y].push_back(x);

    }
    fclose(f);
}
void DFS(int node)
{
    used[node]=1;
    for( vector<int>::iterator 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",res);
    fclose(f);
    fclose(g);
}

int main()
{
    read();
    solve();
    write();
    return 0;
}