#include <stdio.h>
#include <stdlib.h>
int visited[100001];
int n, e;
int main()
{
	FILE* f = fopen("dfs.in", "r");
	fscanf(f, "%d %d", &n, &e);
	int numberGraphs = 0, color = 0;
	int x, y;
	for (int i = 0; i < e; i++) {
		fscanf(f, "%d %d", &x, &y);
		if (!visited[x] && !visited[y]) {
			numberGraphs++;
			color++;
			visited[x] = color;
			visited[y] = color;
		} else if (!visited[x])
			visited[x] = visited[y];
		else if (!visited[y])
			visited[y] = visited[x];
		else {
			//to do
			if (visited[x] != visited[y]) {
				numberGraphs--;
				int aux = visited[x];
				for (int j = 1; j <= n; j++)
					if (visited[j] == aux)
						visited[j] = visited[y];
				//to do parcurg si schimb culoarea
			}
			//else aceeasi culoare deci nimic
		}
	}
	for (int i = 1; i <= n; i++)
		if (!visited[i]) numberGraphs++;
	FILE* g = fopen("dfs.out", "w");
	fprintf(g, "%d", numberGraphs);
	fclose(f);
	fclose(g);
}

/*int n, e;
int visited[100001];
typedef struct edge {
	int leftnode;
	int rightnode;
} edge;

void dfs(int currentNode, int graphColor, edge* edges, int* visited)
{
	if (!visited[currentNode]) {
		visited[currentNode] = graphColor;
		for (int i = 0; i < e; i++) {
			if (edges[i].leftnode == currentNode)
				dfs(edges[i].rightnode, graphColor, edges, visited);
			if (edges[i].rightnode == currentNode)
				dfs(edges[i].leftnode, graphColor, edges, visited);
		}
	}
}

int main()
{
	FILE* f = fopen("dfs.in", "r");
	fscanf(f, "%d %d", &n, &e);
	int numberGraphs = 0;
	edge* edges = (edge*)malloc(e * sizeof(edge));
	for (int i = 0; i < e; i++)
		fscanf(f, "%d %d", &edges[i].leftnode, &edges[i].rightnode);
	for (int i = 1; i <= n; i++) {
		if (!visited[i]) {
			numberGraphs++;
			dfs(i, numberGraphs, edges, visited);
		}
	}
	FILE* g = fopen("dfs.out", "w");
	fprintf(g, "%d", numberGraphs);
	fclose(f);
	fclose(g);
	/*for (int i = 1; i <= n; i++)
		printf("%d ", visited[i]);
}
*/