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

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

vector<vector<int>> G;
vector<bool> v;
int n, m, s, nr, mx = 1;

void Read();
void DFS(int x);

int main()
{
    Read();
    for (int i = 1; i <= n; i++)
    {
        if ( v[i] != 1 )
        {
            nr ++;
            DFS(i);
        }
    }
    fout << nr;
    return 0;
}

void Read()
{
    fin >> n;
    fin >> m;
    G = vector<vector<int>>(n + 1, vector<int>());
    v = vector<bool>(n + 1, 0);
    int x, y;
    for (int i = 1; i <= m; ++i)
    {
        fin >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
}

void DFS(int x)
{
    v[x] = 1;
    for ( const auto& y : G[x] )
    {
        if ( v[y] != 1 )
        {

            DFS(y);
        }
    }
}