#include <iostream>
#include <fstream>
#include <vector>
#define Nmax 100005
using namespace std;
ifstream fin("dfs.in");
ofstream fout("dfs.out");
int N,M,cont;
int Use[Nmax];
vector <int> G[Nmax];

void Read()
{
    fin>>N>>M;
    while(M--)
    {
        int x,y;
        fin>>x>>y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
}

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

void SolveandPrint()
{
    for(int i=1;i<=N;++i)
        if(Use[i]==0)
    {
        DFS(i); cont++;
    }
    fout<<cont<<"\n";
}

int main()
{
    Read(); SolveandPrint();
    return 0;
}