#include <fstream>
#define NMAX 100001

using namespace std;

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

int N, M, nrConex;
int U[NMAX];

struct list {
    int info;
    list *next;
} *G[NMAX];

// graf neorientat

void add(int a, int b) {
    list *q = new list;
    q->info = b;
    q->next = G[a];
    G[a] = q;
}

void dfs(int source) {
    U[source] = 1;
    list *p;
    for(p = G[source]; p; p = p->next)
        if(!U[p->info]) dfs(p->info);
}

int main() {
    int i, a, b;
    fin >> N >> M;
    for(i = 1; i <= M; ++ i) {
        fin >> a >> b;
        add(a, b);
        add(b, a);
    }
    for(i = 1; i <= N; ++ i)
        if(!U[i]) ++ nrConex, dfs(i);
    fout << nrConex << '\n';
    return 0;
}