#include<fstream>
#include<vector>
#include<cstring>
#include<queue>
#define NMAX 100001
using namespace std;

ifstream f("dfs.in");
ofstream g("dfs.out");

void DFS(vector<int>G[], int nod, int viz[]) {
	viz[nod] = 1;
	for (int i = 0; i < G[nod].size(); ++i) {
		if (viz[G[nod][i]] == 0) {
			DFS(G, G[nod][i], viz);
		}
	}

}

int main()
{
	int n, m, x, y, nod, viz[NMAX], nrc = 0;
	vector<int>G[NMAX];
	f >> n >> m >> nod;
	for (int i = 0; i < m; ++i) {
		f >> x >> y;
		G[x].push_back(y);
		G[y].push_back(x);
	}
	memset(viz, 0, sizeof(viz));
	for (int i = 1; i <= n; ++i) {
		if (viz[i] == 0) {
			DFS(G, i, viz);
			++nrc;
		}
	}
	g << nrc;
}