#include <fstream>
#include <vector>
std::vector<int> Nout[100010];
int v[100010];
void dfs(int& s){
	v[s] = 1;
	for (auto&i : Nout[s])
		if (!v[i])dfs(i);
}
int main(){
	std::ifstream f("dfs.in");
	std::ofstream of("dfs.out");
	int N, M, x, y;
	f >> N >> M;
	for (int i = 0; i < M; ++i){
		f >> x >> y;
		Nout[x].push_back(y);
		Nout[y].push_back(x);
	}
	M = 0;
	for (int i = 0; i < N;++i)
		if (!v[i]){ dfs(i); ++M; }
	of << M << "\n";
	return 0;
}