#include <bits/stdc++.h>

using namespace std;
ifstream fin("dfs.in");
ofstream fout("dfs.out");
int n,m;
vector<int> muchii[100005];
bool use[100005];
int ans;
void bfs(int nod)
{
    ans++;
    queue<int> coada;
    coada.push(nod);
    while(!coada.empty())
    {
        int nod=coada.front();
        coada.pop();
        use[nod]=1;
        for(int i:muchii[nod])
            if(!use[i])
        {
            coada.push(i);
            use[i]=1;
        }
    }
}
int main()
{
    fin>>n>>m;
    for(int i=1;i<=m;i++)
    {
        int a,b;
        fin>>a>>b;
        muchii[a].push_back(b);
        muchii[b].push_back(a);
    }
    for(int i=1;i<=n;i++)
        if(!use[i])
            bfs(i);
    fout<<ans;
    return 0;
}