#include <iostream>
#include <fstream>
#include <vector>
#include <queue>

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

vector <int> v[100002];
queue <int> q;

int n, m, i, a, b,cont, freq[100002];

int main()
{
    fin>>n>>m;
    for(i=0; i<m; i++)
    {
        fin>>a>>b;
        v[a].push_back(b);
        v[b].push_back(a);

    }
    for(int j=1; j<=n; j++)
    {
        if(freq[j]!=1)
        {
            q.push(j);
            freq[j]=j;
            cont++;
            while(!q.empty())
            {
                for(int i=0; i<v[q.front()].size(); i++)
                {
                    if(freq[v[q.front()][i]]!=1)
                    {
                        freq[v[q.front()][i]]=1;
                        q.push(v[q.front()][i]);
                    }
                }
                q.pop();
            }

        }

    }
    fout<<cont;
    return 0;
}