#include<stdio.h>
#include<fstream>
#include<stdlib.h>
using namespace std;
typedef struct nod{int x; nod *urm;}NODE;
NODE *v[100005];
int n,m,viz[100005];

void citire()
{
    ifstream f("dfs.in");
    f>>n>>m;
    NODE *q;
    int x,y;
    for(int i=1;i<=m;++i)
    {
        f>>x>>y;
        q=(NODE*)malloc(sizeof(NODE));
        q->x=y;
        q->urm=v[x];
        v[x]=q;
        q=(NODE*)malloc(sizeof(NODE));
        q->x=x;
        q->urm=v[y];
        v[y]=q;
    }
}

void dfs(int nod)
{
    if(viz[nod]) return;
    viz[nod]=1;
    NODE *q=v[nod];
    while(q)
    {
        dfs(q->x);
        q=q->urm;
    }
}

int main()
{
    citire();
    int i,k;
    for(i=1,k=0;i<=n;++i)
        if(!viz[i])  { dfs(i); ++k;  }
    FILE*f=fopen("dfs.out","w");
    fprintf(f,"%d",k);
    fclose(f);
    return 0;
}