// http://infoarena.ro/problema/dfs
#include <fstream>
#include <deque>
using namespace std;

#define maxSize 100001

int nodes,edges,conexComponents;
deque<int> graph[maxSize];
bool visited[maxSize];

void read();
void findConexComponents();
	void depthFirst(int startNode);
void write();

int main() {
	read();
	findConexComponents();
	write();

	return (0);
}

void read() {
	ifstream in("dfs.in");
	int from,to;

	in >> nodes >> edges;
//	graph.resize(nodes+1);
//	visited.resize(nodes+1);

	for(int i=1;i<=edges;i++) {
		in >> from >> to;

		graph[from].push_back(to);
		graph[to].push_back(from);
	}

	in.close();
}

void findConexComponents() {
	for(int i=1;i<=nodes;i++)
		if(!visited[i]) {
			depthFirst(i);
			conexComponents++;
		}
}

void depthFirst(int toVisit) {
	visited[toVisit] = true;

    deque<int>::iterator end = graph[toVisit].end();

	for(deque<int>::iterator it=graph[toVisit].begin();it!=end;it++)
		if(!visited[*it])
			depthFirst(*it);
}

void write() {
	ofstream out("dfs.out");

	out << conexComponents << "\n";

	out.close();
}