//#include <iostream>
#include <fstream>
#include <vector>

using namespace std;
ifstream f("dfs.in");
ofstream g("dfs.out");
const int Nmax = 100005;

bool Use[Nmax];
int n, m, c;
vector <int> G[Nmax];

void Read()
{
    f>>n>>m;
    while(m--)
    {
        int x, y;
        f>>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[Nod].size(); i++)
    {
        int Vecin = G[Nod][i];
        if(Use[Vecin] == 0) DFS(Vecin);
    }
}

void Print()
{
    g<<c<<'\n';
}

int main()
{
    Read();
    for(int i = 1; i <= n; i++)
        if(Use[i] == 0) c++, DFS(i);
    Print();
    return 0;
}