#include<fstream>
#include<vector>
 
using namespace std;
 
 
ifstream f("dfs.in");
ofstream g("dfs.out");

int v[100001];
vector <int> lv[100005];
void dfs(int nod)
{   int i;
    v[nod]=1;
    for(i=0;i<lv[nod].size();i++)
        if(!v[lv[nod][i]])dfs(lv[nod][i]);
}
 
int n,m;
 
int main()
{
    int i;
     
    f>>n>>m;
     
    for( i = 1; i <= m; i++)
    {   
        int x,y;
        f>>x>>y;
        lv[x].push_back(y);
        lv[y].push_back(x);
    }
    int	nr=0;
	
	for(i=1;i<=n;i++)
		if(v[i] !=1 )
		{
			nr++;
			dfs(i);
		}
    
    g<<nr;
}