/*#include <fstream>
#include <vector>
#include <algorithm>
#include <stdio.h>

using namespace std;

ifstream fin("dfs.in");
ofstream fout("dfs.out");

int n,m;

int viz[100005];
typedef struct nod {
    int x;
    nod *next;
}*pNode;

pNode v[100005];

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

void dfs(int x) {
    pNode p;
    viz[x] = 1;
    for(p=v[x]; p; p=p->next) {if (!viz[p->x]) dfs(p->x);}
}

int main() {
    int c=0;
    fin>>n>>m;
    while(m--) {
        int x,y;
        fin>>x>>y;
        add(v[x],y);
        add(v[y],x);
    }
    for(int i=1;i<=n;i++) {
        if(viz[i]==0) {dfs(i);c++;}
    }
    fout<<c;
    return 0;
}*/
#include <stdio.h>

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

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()
{
    freopen("dfs.in","r",stdin);
    freopen("dfs.out","w",stdout);
    scanf("%d %d",&n,&m);
    int i, x, y;

    for (i = 1; i <= m; i++)
    {
        scanf("%d %d",&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);}
    printf("%d\n",cnt);
    return 0;
}