#include<fstream>
using namespace std;
ifstream fin("dfs.in");
ofstream fout("dfs.out");

int a[2000][2000],viz[2000],n,m,cc;

void citire() {
 int i,x,y;
 fin>>n>>m;
 for(i=1;i<=m;i++) {
	 fin>>x>>y;
	 a[x][y]=a[y][x]=1;
 } 
}
void df(int i) {
viz[i]=cc;
//fout<<i<<" ";
for(int k=1;k<=n;k++) if(a[i][k]==1&&viz[k]==0) df(k);
}

int main() {
citire();
for(int i=1;i<=n;i++) 
	if(viz[i]==0) {
		cc++;
		df(i);
		//fout<<"\n";
	}
fout<<cc;
 return 0;
}