#include <bits/stdc++.h>

using namespace std;

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

typedef unsigned long long ull;
typedef long long ll;
typedef pair<int, int> pii;
#define fi first
#define se second

#define NMAX 100005
#define MOD 1000000007
#define INF 0x3f3f3f3f

vector<vector<int>> graf(NMAX);
int n, m, x, y, ans;
bool visited[NMAX];

void read()
{
    in >> n >> m;
    for (int i = 1; i <= m; i++)
    {
        in >> x >> y;
        graf[x].push_back(y);
        graf[y].push_back(x);
    }
}

void DFS(int node)
{
    if (visited[node])
        return;
    
    visited[node] = 1;
    for (auto v : graf[node])
        DFS(v);
}

void solve()
{
    for (int i=1; i<=n; i++)
    {
        if (!visited[i])
            DFS(i), ans++;
    }
    out<<ans;
}

int main()
{
    read();
    solve();
    return 0;
}