#include <iostream>
#include <fstream>

using namespace std;
int N, M;
bool muchii[100][100];
int nr = 0;

bool vizitat[100];

void dfs(int Nod)
{
    vizitat[Nod] = true;
    for (unsigned int i = 1; i <= N; i++)
    {
        if (muchii[Nod][i] == 1 && !vizitat[i])
        {
            dfs(i);
        }      
    }
    
}

void citire()
{
    ifstream in("conexe.in");
    in>>N>>M;

    for (int i = 1; i <= M; i++)
    {
        int x, y;
        in>>x>>y;
        muchii[x][y] = muchii[y][x] = true;
    }

    for (int i = 1; i <= N; i++)
    {
        if(!vizitat[i])
        {
            ++nr;
            dfs(i);
        }
    }
    

}

int main()
{
    citire();
    cout<<nr;
    return 0;
}