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

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

int N,M;
bool A[4001][4001],v[4001];

void DFS(int k)
{
    v[k]=1;
    for(int i=1;i<=N;i++)
        if(A[k][i]&&!v[i])
            DFS(i);
}

int main()
{
    fin>>N>>M;
    for(int i,j,k=1;k<=M;k++)
    {
        fin>>i>>j;
        A[i][j]=A[j][i]=1;
    }
    int nrComp=0;
    for(int i=1;i<=N;i++)
        if(!v[i])
            nrComp++,DFS(i);
    fout<<nrComp;

    return 0;
}