#include<fstream>
#include<vector>

using namespace std;

#define MAX 100005

vector<int> G[MAX];

ifstream fin("dfs.in");
ofstream fout("dfs.out");

int n, m;
int res = 0;
bool folosit[MAX];

void read() {
	fin >> n >> m;
	int x, y;

	for ( int i = 0; i < m; i++ ) {
		fin >> x >> y;
		G[x].push_back(y);
		G[y].push_back(x);
	}
}

void DFS(int node) {
	folosit[node] = true;
	for ( vector<int>::iterator it  = G[node].begin(); it != G[node].end(); it++ )
	{
		if ( !folosit[*it] ) 
			DFS(*it);
	}
}

void rezolva() {
	for ( int i = 1; i <= n; i++ )
	{
		if ( !folosit[i] ){
			DFS(i);
			++res;
		}
	}
}

int main() {
	read();
	rezolva();
	fout << res << "\n";
	return 1;
}