#include <bits/stdc++.h>
#define Nmax 100005

using namespace std;
ifstream f("dfs.in");
ofstream g("dfs.out");
// Praise Stalin or go to gulag, kamarad.
int nrNode, nrEdge, cnt;
bool viz[Nmax];
vector <int> ourvector[Nmax];

void DFS(int node)
{
    viz[node] = 1;
    ++cnt;
    for (int i = 0; i < (int)ourvector[node].size(); ++i) {
        int x = ourvector[node][i];
        if (!viz[x]) {
            DFS(x);
        }
    }
}

int main()
{

    f >> nrNode >> nrEdge;
    int x, y;
    for (int i = 0; i < nrEdge; ++i) {
        f >> x >> y;
        ourvector[x].push_back(y);
        ourvector[y].push_back(x);
    }
    DFS(1);
    for (int i = 1; i <= nrNode; ++i) {
        if (!viz[i]) {
            ++cnt;
            DFS(i);
        }
    }
    g << cnt;
    return 0;
}