#include <iostream>
#include <fstream>

using namespace std;

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

const int N = 100003;

int n, m, nr, lst[N], vf[4*N], urm[4*N], nrc;
bool viz[N];

void adauga( int x, int y )
{
    nr++;
    vf[nr] = y;
    urm[nr] = lst[x];
    lst[x] = nr;
}

void dfs( int x )
{
    viz[x] = true;
    int p = lst[x], y;
    while( p != 0 )
    {
        y = vf[p];
        if ( viz[y] == false )
            dfs(y);
        p = urm[p];
    }
}

int main()
{
    int i, x, y;
    in >> n >> m;
    for ( i = 1; i <= m; i++ )
    {
        in >> x >> y;
        adauga(x, y);
        adauga(y,x);
    }
    for ( i = 1; i <= n; i++ )
    {
        if ( viz[i] == false )
        {
            nrc++;
            dfs(i);
        }
    }
    out << nrc;
    return 0;
}