#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <algorithm>

using namespace std;

int32_t parent[100000];
int32_t ans = 0;

void make_set(int v) {
	parent[v] = v;
}

int find_set(int v) {
	if (v == parent[v])
		return v;
	return parent[v] = find_set(parent[v]);
}

void union_sets(int a, int b) {
	a = find_set(a);
	b = find_set(b);
	if (a != b)
	{
		parent[b] = a;
		ans -= 1;
	}
}

const int blocksize = 2000;

int main()
{
	int32_t n = 0, m = 0;
	auto fin = fopen("input.bin", "rb");
	auto fout = fopen("output.bin", "wb");
	fread(reinterpret_cast<char *>(&n), 4, 1, fin);
	fread(reinterpret_cast<char *>(&m), 4, 1, fin);
	ans = n;

	for (int i = 0; i < n; ++i)
	{
		make_set(i);
	}

	int32_t a[blocksize];

	for (int i = 0; i < m; i += blocksize)
	{
		fread(reinterpret_cast<char *>(&a), 4, min(blocksize, (m - i) * 2), fin);
		for (int j = 0; j < min(blocksize, (m - i) * 2); j += 2)
		{
			union_sets(a[j], a[j + 1]);
		}
	}

	fwrite(&ans, 4, 1, fout);

	fclose(fin);
	fclose(fout);
	return 0;
}