#include <fstream>
#include <vector>
using namespace std;

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

const int NMax = 100000;

int N,M,Sol;
vector <int> G[NMax + 5];
int Use[NMax + 5];

void Read()
{
    fin>>N>>M;
    for(int i = 1; i<=M; i++)
        {
            int x,y;
            fin>>x>>y;
            G[x].push_back(y);
            G[y].push_back(x);
        }
}


void DFS(int Nod)
{
    Use[Nod] = 1;

    for(int i = 0; i < (int) G[i].size(); i++)
        {
            int Vecin = G[Nod][i];
            if(!Use[Vecin])
                DFS(Vecin);
        }
}

void Solve()
{
    for(int  i = 1; i<=N; i++)
        if(!Use[i])
        {
            Sol++;
            DFS(i);
        }

}

void Print()
{
    fout<<Sol<<"\n";
}

int main()
{
    Read();
    Solve();
    Print();
    return 0;
}