/*
   ~Keep it Simple!~
*/

#include <stdio.h>
#include <list>
using namespace std;

int n,m,nrc;
list<int> drumuri[100001];
bool c[100001];

void DDFS(int x)
{
    c[x]=1;
    for(list<int>::iterator it = drumuri[x].begin(); it!=drumuri[x].end(); it++)
      if(c[*it]==0)
       DDFS(*it);
}
void DFS()
{
    for(int i=1;i<=n;i++)
    {
        if(c[i]==0)
        {
          DDFS(i);
          nrc++;
        }
    }
}

int main()
{
    freopen("dfs.in","r",stdin);
    freopen("dfs.out","w",stdout);

    scanf("%d%d",&n,&m);

    int x,y;
    for(int i=1;i<=m;i++)
    {
        scanf("%d%d",&x,&y);
        drumuri[x].push_back(y);
        drumuri[y].push_back(x);
    }

    DFS();
    printf("%d",nrc);
}