#include <iostream>
#include <vector>
#include <stdio.h>
#define NMax 100005
using namespace std;
vector<int> Graf[NMax];
int N,M,x,y,z,dist[NMax],NumarComponente;
bool mark[NMax];

void Read()
{
    scanf("%d%d",&N,&M);
    for(int i=1;i<=N;i++)
    {
        scanf("%d%d",&x,&y);
        Graf[x].push_back(y);
        Graf[y].push_back(x);
    }
}

void DFS(int nod)
{
    mark[nod]=true;
    for(vector<int>::iterator it=Graf[nod].begin();it!=Graf[nod].end();it++)
        if(mark[*it]==false)
            DFS(*it);
}

void Componente()
{
    for(int nod=1;nod<=N;nod++)
        if(mark[nod]==false)
        {
            NumarComponente=NumarComponente+1;
            DFS(nod);
        }
}

void Write()
{
    printf("%d",NumarComponente);
}

int main()
{
    freopen("dfs.in","r",stdin);
    freopen("dfs.out","w",stdout);
    Read();
    Componente();
    Write();
}