#include <fstream>

using namespace std;

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

int tata[100000], niv[100000];

int fnd(int x)
{
    int y = x, r = x;
    while(tata[r] != 0)
    {
        r = tata[r];
    }
    while(tata[y] != 0)
    {
        int z = tata[y];
        tata[y] = r;
        y = z;
    }
    return r;
}

void uni(int x, int y)
{
    int t1 = fnd(x), t2 = fnd(y);

    if(t1 != t2)
    {
        if(niv[t1] < niv[t2])
        {
            tata[t1] = t2;
        }
        else
        {
            tata[t2] = t1;
        }
        if(niv[t1] == niv[t2]){
            tata[t2] = t1;
            niv[t1]++;
        }
    }
}

int main()
{
    int n, m;
    fin >> n >> m;
    for(int i = 1; i <= m; i++)
    {
        int a, b;
        fin >> a >> b;
        uni(fnd(a), fnd(b));
    }
    int nr = 0;
    for(int i = 1; i <= n; i++)
    {
        if(tata[i] == 0)
        {
            nr++;
        }
    }
    fout << nr;

    return 0;
}