#include <fstream>
#include <vector>
#define NMax 100005
using namespace std;
ifstream fin("dfs.in");
ofstream fout("dfs.out");
vector <int> G[NMax];
int N, M, X, Y,Use[NMax],Sol;
void Read()
{
    fin>>N>>M;
    for(int i=1; i<=M; i++)
    {
        fin>>X>>Y;
        G[X].push_back(Y);
        G[Y].push_back(X);
    }
}
 
void DFS(int nod)
{
    Use[nod]=1;
    for(unsigned int i=0; i<G[nod].size(); i++)
        if(!Use[G[nod][i]]) DFS(G[nod][i]);
}
 
void Print()
{
    fout<<Sol<<'\n';
 
}
int main()
{
    Read();
    for(int i=1;i<=N;i++)
        if(!Use[i])
        {
            Sol++;
            DFS(i);
        }
 
    Print();
    return 0;
}