#include <cstdio>
#include <stack>
#include <vector>

using namespace std;

#define file_in "dfs.in"
#define file_out "dfs.out"

#define nmax 101000

stack<int> St;
vector<int> G[nmax];
int viz[nmax];
int N,M,a,b,i,ans;

void dfs(int nod){
	
	int X;
	St.push(nod); //bag nodul in stiva
	while(!St.empty()){//stiva nu e goala
		X=St.top();
		St.pop();
		viz[X]=1;
		for (vector<int> :: iterator it=G[X].begin();it!=G[X].end();++it)
			if (!viz[*it]){
				viz[*it]=1;
				St.push(*it);//il bag in stiva
			}
	}
}

int main(){
	
	freopen(file_in,"r",stdin);
	freopen(file_out,"w",stdout);
	
	scanf("%d %d", &N, &M);
	
	while(M--){
		
		scanf("%d %d", &a, &b);
		
		G[a].push_back(b);
		G[b].push_back(a);
		
	}
	
	ans=0;
	for (i=1;i<=N;++i)
		 if (!viz[i]){
			 ans++;
			 dfs(i);
		 }
		 
	printf("%d\n", ans);

	return 0;
}