#include <stdio.h>
#include <fstream.h> 
ifstream f("dfs.in");
ofstream g("dfs.out");
int a[1005][1005], n, m, v[1005], nr;
void citire(){
	f>>n>>m;
	int i, x, y;
	for (i = 1; i <= m; i++){
		f>>x>>y;
		a[x][y] = a[y][x] = 1;
	}
}
void DFS(int nod){
	int i;
	v[nod] = 1;
	for (i = 1; i <= n; i++) 
		if (v[i]==0 && a[nod][i]==1) 
			DFS(i);
}  
 
int main(){
citire();
int i;
for (i = 1; i <= n; i++) 
	if (v[i]==0){ 
		nr++; 
		DFS(i);
	}
g<<nr<<"\n";
return 0;
}