#include <fstream>
#include <vector>
#include <deque>

using namespace std;
ifstream f("dfs.in");
ofstream g("dfs.out");
vector<int> v[100010];
int n,m,i,x,y,viz[100010];
deque<int> q;
void bfs(int);
int main()
{
    f>>n>>m;//citire graf neorientat
    for(;m;m--)
    {
        f>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);

    }
    for(i=1;i<=n;i++)
        if(!viz[i])
        {
            m++;
            bfs(i);
        }
    g<<m<<'\n';
    return 0;
}
void bfs(int nod)//!!!
{
    viz[nod]=1;
    q.push_back(nod);
    for(;q.size();)
    {
       x=q.front();
       q.pop_front();
        for(auto vec:v[nod])
            if(!viz[vec])
            {
                viz[vec]=1;
                q.push_back(vec);
            }
    }

}