#include <stdio.h>
#include <stdlib.h>
#include <string.h>

typedef struct vectorInt {
	int* data;
	int size;
	int capacity;
} vectInt;
typedef vectInt* vector;

vector vec_new(int initCap) {
	if(initCap < 10) {
		initCap = 10;
	}
	vector vect = (vector)malloc(sizeof(vectInt));
	vect->capacity = initCap;
	vect->size = 0;
	vect->data = (int*)malloc(vect->capacity * sizeof(int));
	return vect;
}

void vec_free(vector vect) {
	free(vect->data);
	free(vect);
}

void vec_push_back(vector vect, int val) {
	if(vect->size == vect->capacity) {
		vect->capacity = 2 * vect->capacity;
		int* newData = (int*)malloc(vect->capacity * sizeof(int));
		memcpy(newData, vect->data, vect->size * sizeof(int));
		free(vect->data);
		vect->data = newData;
	}
	vect->data[vect->size] = val;
	vect->size++;
}

void vec_demo() {
	vector vect = vec_new(0);
	int i;
	for(i=0; i<50; i++) {
		vec_push_back(vect, 2 * i);
	}
	for(i=0; i<vect->size; i++) {
		printf("vect[%d]=%d\n", i, vect->data[i]);
	}
	printf("vect->size=%d\n", vect->size);
	printf("vect->capacity=%d\n", vect->capacity);
	vec_free(vect);
}

void dfs(int x, vector* g, int* state) {
	if(state[x] == 0) {
		state[x] = 1;
		int i;
		for(i=0; i<g[x]->size; i++) {
			dfs(g[x]->data[i], g, state);
		}
	}
}

int main() {
	FILE* fin = fopen("dfs.in", "r");
	int n, m;
	fscanf(fin, "%d %d\n", &n, &m);
	int i;
	vector* g = (vector*)malloc((n + 1) * sizeof(vector));
	for(i=0; i<=n; i++) {
		g[i] = vec_new(0);
	}
	int x, y;
	for(i=0; i<m; i++) {
		fscanf(fin, "%d %d\n", &x, &y);
		vec_push_back(g[x], y);
		vec_push_back(g[y], x);
	}
	fclose(fin);
	int* state = (int*)calloc(n + 1, sizeof(int));
	int nb = 0;
	
	for(i=1; i<=n; i++) {
		if(state[i] == 0) {
			nb++;
			dfs(i, g, state);
		}
	}
	
	FILE* fout = fopen("dfs.out", "w");
	fprintf(fout, "%d\n", nb);
	fclose(fout);
	free(state);
	for(i=0; i<=n; i++) {
		free(g[i]);
	}
	free(g);
	return 0;
}