#include <cstdio>

using namespace std;

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

struct graf{
    int x;
    graf* urm;
}*a[100003];

void add(graf *&a,int x)
{
    graf *q=new graf;
    q->x=x;
    q->urm=a;
    a=q;
}

void read()
{
    int y,z;
    scanf("%d %d",&n,&m);
    for (int i=1;i<=m;i++)
    {
        scanf("%d %d",&y,&z);
        add(a[y],z);
        add(a[z],y);
    }
}

void dfs(int nod)
{
    graf *q;
    q=a[nod];
    while (q!=NULL)
    {
        if (viz[q->x]==0)
        {
            viz[q->x]=1;
            dfs(q->x);
        }
        q=q->urm;
    }
}

void solve()
{
    for (int i=1;i<=n;i++)
        if (viz[i]==0)
        {
            nr++;
            dfs(i);
        }
    printf("%d",nr);
}

int main()
{
    freopen("dfs.in","r",stdin);
    freopen("dfs.out","w",stdout);
    read();
    solve();
    return 0;
}