#include<stdio.h>
#define MAX 300001
int n,m,v[2][MAX],cont;
void add(int x,int y)
{
	if(!v[1][x])
	{
		v[1][x] = cont;
		v[0][cont] = y;
		v[1][cont] = 0;
	}
	else
	{
		v[1][v[0][x]] = cont;
		v[0][cont] = y;
		v[1][cont] = 0;		
	}
	v[0][x] = cont;
}
void df(int i)
{
	int var;
	while(v[1][i]>0)
	{
		var = v[1][i];
		v[1][i] = v[1][v[1][i]];
		
		//if(!v[1][i])v[1][i] = -1;
		df(v[0][var]);
	}
}
int main()
{
	FILE*f = fopen("dfs.in","r");
	fscanf(f,"%d %d",&n,&m);
	int i,a,b;
	cont = n+1;
	for(i=1;i<=m;++i,++cont)
	{
		fscanf(f,"%d%d",&a,&b);
		add(a,b);
		++cont;
		add(b,a);
	}
	fclose(f);
	for(i = 1,cont = 0;i<=n;++i)
	{
		if(v[1][i]>=0)
		{
			++cont;
			df(i);
		}
	}
	FILE*g = fopen("dfs.out","w");
	fprintf(g,"%d\n",cont);
	fclose(g);
	return 0;
}