#include <fstream>
#include <vector>
#include <bitset>

#define ARR_MAX 100005

using namespace std;

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

int V, m, x, y, connected, urm;
vector<int> adj[ARR_MAX];
vector<int> Result;
bitset<ARR_MAX> visited;


void ReadGraph()
{
    fin >> V >> m;
    for(int i = 0; i < m; i++) {
        fin >> x >> y;

        adj[x].push_back(y);
        adj[y].push_back(x);
    }
}

void DFS(int v)
{
    visited[v] = 1;

    for(unsigned i = 0; i < adj[v].size(); i++) {
        urm = adj[v][i];
        if(!visited[urm])
            DFS(urm);
    }
}

void Write()
{
    for(int i = 1; i <= V; i++){
        if(!visited[i])
            connected++;

        DFS(i);
    }

    fout << connected;
}

int main()
{
    ReadGraph();
    Write();
}