#include <stdio.h>
#include <queue>

using namespace std;

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

struct nod
{
    int inf;
    nod *urm;
}*v[100010];

int viz[100010],s[100010];

void adaug(nod *&prim,int x)
{
    nod* nou;
    nou = new nod;
    nou->inf=x;
    nou->urm=prim;
    prim=nou;
}

void DF(int i)
{
    nod *j;
    viz[i]=1;
    for (j=v[i];j!=NULL;j=j->urm)
        if (!viz[j->inf]) DF(j->inf);
}

int main()
{
    int n,m,i,x,y,nr=0;
    fscanf(f,"%d%d",&n,&m);
    for (i=1;i<=m;i++)
    {
        fscanf(f,"%d%d",&x,&y);
        adaug(v[x],y);
        adaug(v[y],x);
    }
    for (i=1;i<=n;i++)
    {
        if (!viz[i]) {DF(i);nr++;}
    }
    fprintf(g,"%d",nr);
    fclose(f);
    fclose(g);
    return 0;
}