#include<stdio.h>
#include<vector>
using namespace std;
int find(int* parent,int val) {
	if(parent[val]!=val)
		parent[val]=find(parent,parent[val]);//find the leader of the group of this node
	return parent[val];
}

void unionSet(int* parent,int a,int b) {
	int ap = find(parent,a);
	int bp = find(parent,b);
	if(ap!=bp)
		parent[bp]=ap; //make 'a's parent as the leader of b's group as well.
}
int countNumberOfComponents(vector<vector<int>>& M) {
	int n = M.size();
	int parent[n]; //stores parent for each node
	for(int i=0;i<n;i++) parent[i]=i; //initially every node is individual
	for(int i=0;i<n;i++) {
		for(int j=i+1;j<n;j++) {
			if(M[i][j] && parent[i]!=parent[j]) {
				unionSet(parent,i,j); // if there is an edge, but parents are different that means these
				  // two nodes(and hence the tress asociated with them) can be clubbed
			}
		}
	}
//this now counts number of components.
	int count=0;
	for(int i=0;i<n;i++) {
	   if(parent[i]==i) count++;
	}
	return count;
}

int main() {
	int vertices,edges,from,to;
	scanf("%d%d",&vertices,&edges);
	vector<vector<int> > adjacencyMatrix(vertices, vector<int>(vertices,0));
	for(int i=0;i<edges;i++)
	{
		scanf("%d%d",&from,&to);
		adjacencyMatrix[from][to]=adjacencyMatrix[to][from]=1;
	}
	printf("%d",countNumberOfComponents(adjacencyMatrix));
	return 0;
}