# include <bits/stdc++.h>

# define ins push_back

using namespace std;

int n, m, x, y;
const int Nmax = 100000 + 5;

vector <int> GF[Nmax];
int ap[Nmax];

void dfs(int node) {

    ap[node] = x;

    for (int i = 0; i < GF[node].size(); ++i)
          if (!ap[GF[node][i]]) dfs(GF[node][i]);

}

int main ()
{
    freopen("dfs.in", "r", stdin);
    freopen("dfs.out", "w", stdout);

    scanf("%d %d\n", &n, &m);

    for (int i = 1; i <= m; ++i){
        scanf("%d %d", &x, &y);
        GF[x].ins(y), GF[y].ins(x);
    }

    int ans = 0;

    for (int i = 1; i <= n; ++i)
        if (!ap[i]) {
            dfs(i);
            ++ans;
        }

    printf("%d\n", ans);

    return 0;
}