/*
 * paduri de multimi disjuncte
 * */
#include <fstream>
#define NMAX 100001
using namespace std;

int tata[NMAX], h[NMAX], n, nrc;

int root(int x){
	int y=x,tmp;
	while(tata[y])
		y=tata[y];
	while(x-y){
		tmp=x;
		x=tata[x];
		tata[tmp]=y;
	}
	return y;
}

int main(){
	ifstream fin("dfs.in");
	ofstream fout("dfs.out");
	int m,i,j,ri,rj;
	fin>>n>>m;
	nrc=n;
	for( ; m ;--m){
		fin>>i>>j;
		ri=root(i);
		rj=root(j);
		if(ri != rj){
			if(h[ri]>h[rj])
				tata[rj]=ri;
			else
				if(h[ri] < h[rj])
					tata[ri] = rj;
				else{
					tata[ri]=rj;
					h[rj]++;
				}
			nrc--;
		}
	}
	fout<<nrc;
	return 0;
}