#include <bits/stdc++.h>

#define NMax 100005

using namespace std;

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

int N,M;
vector<int> G[NMax];
bool mark[NMax];

void Read()
{
    fin>>N>>M;
    for(int i,j,k=1;k<=M;k++)
    {
        fin>>i>>j;
        G[i].push_back(j);
        G[j].push_back(i);
    }
}

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

int main()
{
    Read();
    int conexe=0;
    for(int i=1;i<=N;i++)
        if(!mark[i])
            DFS(i), conexe++;
    fout<<conexe;

    return 0;
}