#include <bits/stdc++.h>
using namespace std;
ifstream fin("dfs.in");
ofstream fout("dfs.out");
int n,m,cnt,viz[100005];
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()
{
    fin >> n >> m;
    int x, y;
    for (int i=1;i<=m;i++){
        fin >> 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();
    for (int i=1;i<=n;i++){
        if (!viz[i]){
            cnt++;
            dfs(i);
        }
    }
    fout << cnt << '\n';
    return 0;
}