#include <iostream>
#include <fstream>

using namespace std;

int n, m, viz[100005], cnt;

ifstream f("dfs.in");
ofstream g("dfs.out");

typedef struct nod{
int x;
nod *a;
} *pNod;
pNod v[100005];

void add(pNod &dest, int val)
{
    pNod p;
    p=new nod;
    p->x = val;
    p->a =dest;
    dest = p;
}

void citire()
{
    f>>n>>m;
    int i,x,y;
    for (i=1;i<=m;i++)
    {
        f>>x>>y;
        add(v[x],y);
        add(v[y],x);
    }
}

void DFS(int nod)
{
    pNod p;
    viz[nod] = 1;
    for(p=v[nod];p!=NULL;p=p->a)
        if(!viz[p->x])
        DFS(p->x);
}

int main()
{
    citire();
    int i;
    for(i=1;i<=n;i++)
        if(!viz[i])
    {
        cnt++;
        DFS(i);
    }
    g<<cnt;
}