#include <iostream>
#include <cstdio>
#include <vector>
using namespace std;
int n,m;
vector <int>  lv[100020];
void citire( )
{
    int x,y;
    FILE *f=fopen("dfs.in","r");
    fscanf(f,"%d%d",&n,&m);
    for(int i=1;i<=m;i++)
    {
       fscanf(f,"%d%d",&x,&y);
       lv[x].push_back(y);
       lv[y].push_back(x);

    }

}
int used[100020];
void dfs(int nc)
{
     vector <int>:: iterator ii;
     used[nc]=1;
     for(ii=lv[nc].begin();ii!=lv[nc].end();ii++)
        if(!used[*ii])
             dfs(*ii);
}
int nr=0;
void rez( )
{
    for(int i=1;i<=n;i++)
        if(!used[i])
    {
        nr++;
        dfs(i);
    }
   FILE *f1=fopen("dfs.out","w");
   fprintf(f1,"%d",nr);
}
int main()
{
   citire();
   rez();
    return 0;
}