#include <stdio.h>
#include <vector>
#define MAX 100005
using namespace std;

FILE*f=fopen("dfs.in","r");
FILE*g=fopen("dfs.out","w");

int nod,nod2,n,m,conex,viz[MAX];
vector<int> mat[MAX];

void citire(){
	int i;
	fscanf(f,"%d %d",&n,&m);
	for(i=0;i<m;i++){
		fscanf(f,"%d %d",&nod,&nod2);
		mat[nod].push_back(nod2);
		mat[nod2].push_back(nod);
	}
}

void afis(){
	int i,j;
	for(i=0;i<n;i++){
		for(j=0;j<mat[i].size();j++){
			printf("%d ",mat[i][j]);
		}
		printf("\n");
	}
}

void dfs(int i){
	int j;
	viz[i]=1;
	for(j=0;j<mat[i].size();j++){
		if(!viz[mat[i][j]]){
			dfs(mat[i][j]);
		}
	}
}

int main(){
	int i;
	citire();
	for(i=1;i<=n;i++){
		if(!viz[i]){
			viz[i]=1;
			dfs(i);
			conex++;
		}
	}
	//afis();
	fprintf(g,"%d\n",conex);
	fclose(f);
	fclose(g);
	return 0;
}