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

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

vector <int> G[100005];
int Use[100005];
int N,M,Sol;

void DFS(int Nod)
{
Use[Nod] = 1;
for(unsigned int i=0;i<G[Nod].size();i++)
{
    int Vecin=G[Nod][i];
    if(!Use[Vecin])
        DFS(Vecin);
}
}

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

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

    Print();
    return 0;
}