#include <cstdio>
#include <vector>

const int MAXN = 1e5;

std::vector <int> g[MAXN + 1];
bool r[MAXN + 1];

void dfs(int u) {
  r[u] = 1;
  for (int i = 0; i < g[u].size(); ++i) {
    if (!r[g[u][i]]) {
      dfs(g[u][i]);
    }
  }
}

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