#include <cstdio>
#include <vector>
using namespace std;
const int NMAX = 100505;
int n, m;
vector<int> G[NMAX];
bool mark[NMAX];

void read() {
  scanf("%d%d", &n, &m);
  int x, y;
  for (int i = 1; i <= m; i++) {
    scanf("%d%d", &x, &y);
    G[x].push_back(y); G[y].push_back(x);
  }
}

void dfs(int node) {
  mark[node] = true;
  for (auto it = G[node].begin(); it != G[node].end(); it++)
    if (!mark[*it])
      dfs(*it);
}

void solve() {
  int res = 0;
  for (int i = 1; i <= n; i++)
    if (!mark[i]) {
      dfs(i);
      res++;
    }
  printf("%d\n", res);
}

int main() {
  freopen("dfs.in", "r", stdin);
  freopen("dfs.out", "w", stdout);
  
  read();
  solve();
  return 0;
}