#include<stdio.h>
int a[2000][2000],viz[2000],n,m,k;

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

void citire(){
    int x,y;
    fscanf(f,"%ld %ld",&n,&m);
    for(int i=1;i<=m;i++){
		fscanf(f,"%ld %ld",&x,&y);
		a[x][y]=1;
		a[y][x]=1;
	}
}
void dfs(int nod){
	viz[nod]=1;
	for(int i=1;i<=n;i++)
		if(viz[i]!=1 && a[nod][i]!=0)
			dfs(i);
}
int main(){	
	citire();
	for(int i=1;i<=n;i++)
		if(viz[i]!=1){
			dfs(i);k++;
	}
	fprintf(g,"%ld",k);
	fclose(f);
	fclose(g);
	return 0;
}