#include <fstream>
#include <vector>
#include <bitset>
#define NMAX 100002

using namespace std;

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

vector<int> V[NMAX];
bitset<NMAX> Viz;
int M,N,K,x,y;

void DFS(int nod)
{
    vector<int>::iterator it,sf;
    Viz[nod] = 1;
    for(it=V[nod].begin(),sf=V[nod].end();it<sf;++it)
        if(!Viz[*it])
            DFS(*it);
}

int main()
{
    in>>N>>M;
    while(M--)
    {
        in>>x>>y;
        V[x].push_back(y);
        V[y].push_back(x);
    }
    for(x=1;x<=N;x++)
        if(!Viz[x])
            ++K,DFS(x);
    out<<K<<'\n';
    return 0;
}