#include<vector>
#include<fstream>
#include<queue>

using namespace std;
const int MaxN=100005;
vector <int> v[MaxN];
ifstream fin ("dfs.in");
ofstream fout ("dfs.out");
int n,m,i,x,y,viz[MaxN],k;
queue<int> q;

void bfs(int nod, int k)
{
    q.push(nod);
    viz[nod]=k;
    while(!q.empty())
    {
        int nod=q.front();
        q.pop();
        for(i=0;i<v[nod].size();i++){
            if(!viz[v[nod][i]]){
                viz[v[nod][i]]=k;
                q.push(v[nod][i]);
            }
        }
    }
}
int main()
{

    fin>>n>>m;
    for(i=1;i<=m;i++){
        fin>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }

    k=0;
    for(i=1;i<=n;++i)
    {
        if(!viz[i])
        {
            ++k;
            bfs(i,k);
        }
    }

    fout<<k;
    fin.close();
    fout.close();
return 0;
}