#include <iostream>
#include <fstream>
#include <stack>
#include <vector>

#define NMax 100005

using namespace std;

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

int N;
bool VIZ[NMax];
vector <int> Muchie[NMax];

void DFS(int nodStart)
{
    stack <int> Stiva;
    Stiva.push(nodStart);

    while( !Stiva.empty() )
    {
        int nodCurent = Stiva.top();
        Stiva.pop();

        for(unsigned int i = 0; i < Muchie[nodCurent].size(); ++ i)
            if(VIZ[Muchie[nodCurent][i]] == false)
            {
                VIZ[Muchie[nodCurent][i]] = true;
                Stiva.push(Muchie[nodCurent][i]);
            }
    }
}

int main()
{
    int M, X, Y;
    fin >> N >> M;

    for(int i = 1; i <= M; ++ i)
    {
        fin >> X >> Y;

        Muchie[X].push_back(Y);
        Muchie[Y].push_back(X);
    }

    int comp_conexe = 0;
    for(int i = 1; i <= N; ++ i)
        if(VIZ[i] == false)
        {
            comp_conexe ++;
            DFS(i);
        }

    fout << comp_conexe;

    return 0;
}