#include <fstream>
#include <queue>
#include <vector>
#include <cstring>

using namespace std;

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

int N, M;
int sol;
vector<int> V[100001];
queue<int> Q;
bool viz[100001];

void BF(int nod)
{
    while (!Q.empty())
    {
        int top = Q.front();
        Q.pop();
        for (vector<int>::iterator it = V[top].begin(); it != V[top].end(); ++it)
        {
            if (!viz[*it])
            {
                viz[*it] = true;
                Q.push(*it);
            }
        }
    }
}

int main()
{
    fin >> N >> M;
    for (int i = 1, nod1, nod2; i <= M; ++i)
    {
        fin >> nod1 >> nod2;
        V[nod1].push_back(nod2);
        V[nod2].push_back(nod1);
    }

    for (int i = 1; i <= N; ++i)
    {
        if (!viz[i])
        {
            ++sol;
            viz[i] = true;
            Q.push(i);
            BF(i);
        }
    }

    fout << sol;

    fin.close();
    fout.close();
    return 0;
}