#include <bits/stdc++.h>
#define FOR(n) for(int i=1;i<=n;++i)
using namespace std;

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

const int NMAX = 1e5+5;
vector<int>adj[NMAX];
bool viz[NMAX];
int n, m, ans;

inline void dfs(const int &x)
{
    viz[x] = 1;
    for(auto itr : adj[x])
    {
        if(!viz[itr])
            dfs(itr);
    }
}

inline void solve()
{
    for(int i=1;i<=n;++i)
    {
        if(viz[i] == 0)
        {
            dfs(i);
            ans++;
        }
    }
    fout << ans;
}

int main()
{
    fin >> n >> m;
    FOR(m)
    {
        int x, y;
        fin >> x >> y;
        adj[x].push_back(y);
        adj[y].push_back(x);
    }
    solve();
}