#include <fstream>
#include <cstdio>

using namespace std;

ofstream cout("dfs.out");

int n,m,a,b,k;
bool viz[100005];
struct nod{
    int inf;
    nod *urm;
}*L[100005];

inline void add(const int &a, const int &b){
    nod *p=new nod;
    p->inf=b;
    p->urm=L[a];
    L[a]=p;
}

inline void DFS(int x){
    int i;
    for(nod *p=L[x];p;p=p->urm)
        if(!viz[p->inf])
            viz[p->inf]=1,DFS(p->inf);
}

int main()
{
    FILE*cin=freopen("dfs.in","r",stdin);
    scanf("%d%d",&n,&m);
    for(int i=1;i<=m;i++){
        scanf("%d%d",&a,&b);
        add(b,a);
        add(a,b);
    }
    for(int i=1;i<=n;i++)
        if(!viz[i])
            DFS(i),k++;
    cout<<k;
    return 0;
}