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

typedef struct vertex_node {
	int value;
	struct vertex_node *next;
} vertex_node;

typedef struct graphVertex {
	int numNodes;
	int numEdges;
	vertex_node *nodes[100001];
} graphVertex;
graphVertex graf;

void legare_noduri_lista(vertex_node **listStart, int value)
{
	vertex_node *nou;
	nou = malloc(sizeof(vertex_node *));
	nou->value = value;
	nou->next = *listStart;
	*listStart = nou;
}

void read_graphVertex()
{
	int dim1, dim2;
	int nod1, nod2;
	FILE *fin;
	fin = fopen("dfs.in", "r");
	fscanf(fin, "%d %d", &dim1, &dim2);
	graf.numNodes = dim1;
	graf.numEdges = dim2;
	for (int i = 0; i < graf.numEdges; i++) {
		fscanf(fin, "%d %d", &nod1, &nod2);
		legare_noduri_lista(&graf.nodes[nod1], nod2);
		legare_noduri_lista(&graf.nodes[nod2], nod1);
	}
	fclose(fin);
}
void marcheaza_DFS(int nod_curent, int *vizitat)
{
	vertex_node *listStart;
	vizitat[nod_curent] = 1;
	for (listStart = graf.nodes[nod_curent]; listStart != NULL; listStart = listStart->next)
		if (!vizitat[listStart->value])
			marcheaza_DFS(listStart->value, vizitat);
}
void numara_conexe(int *vizitat, int *contor)
{
	for (int i = 0; i < graf.numNodes; i++)
		if (!vizitat[i]) {
			(*contor)++;
			marcheaza_DFS(i, vizitat);
		}
}
int main()
{
	FILE *fout;
	int vizitat[100001];
	read_graphVertex();
	int contor = 0;
	numara_conexe(vizitat, &contor);
	fout = fopen("dfs.out", "w");
	fprintf(fout, "%d", contor);
	fclose(fout);
	return 0;
}