#include <stdio.h>
#include <stdlib.h>
#define NMAX 200000

int n, m, nr, vf[1 + 2 * NMAX], urm[1 + 2 * NMAX], lst[1 + NMAX], viz[1 + NMAX];
int st, dr;

void adauga ( int x, int y ) {
    ++nr;
    vf[nr] = y;
    urm[nr] = lst[x];
    lst[x] = nr;
}

void dfs(int node) {
    int p = lst[node];
    viz[node] = 1;
    while (p != 0) {
        int y = vf[p];
        if (viz[y] == 0)
            dfs(y);
        p = urm[p];
    }
}

int main() {
    FILE *fin = fopen("dfs.in", "r");
    fscanf(fin, "%d%d", &n, &m);
    int i;
    for (i = 1; i <= m; ++i) {
        int x, y;
        fscanf(fin, "%d%d", &x, &y);
        adauga(x, y);
        adauga(y, x);
    }
    fclose(fin);
    int cnt = 0;
    FILE *fout = fopen("dfs.out", "w");
    for (i = 1; i <= n; i++) {
        if (!viz[i]) {
            cnt++;
            dfs(i);
        }
    }
    fprintf(fout, "%d\n",cnt);
    fclose( fout );
    return 0;
}