#include <fstream>
#include <vector>

int Nr=0;
int v[100000];
std::vector<int> g[100000];

void dfs(int i){
	v[i] = 1;
	for (auto d : g[i]){
		if (!v[d]) dfs(d);
	}
}

int main(){
	std::ifstream f("dfs.in");
	std::ofstream c("dfs.out");
	int a, b,n;
	f >> n >> a;
	while (f >> a >> b) { g[a].push_back(b); g[b].push_back(a); }
	for (int i = 1; i <= n; ++i)
		if (!v[i]){ Nr++; dfs(i); }
	
	c << Nr << '\n';
	return 0;
}