/* 
 * File:   main.cpp
 * Author: zalman
 *
 * Created on March 15, 2011, 12:37 PM
 */

#include <cstdio>
#include <vector>
#include <iostream>
#include <fstream>
#define NMAX 100005
using namespace std;

int N, M, x, y, cnt;
vector<int> V[NMAX];
bool viz[NMAX];

void read(void)
{
    FILE *f = fopen("dfs.in","r");
    fscanf(f,"%d%d", &N, &M);
    while(M--)
    {
        fscanf(f, "%d%d", &x, &y);
        V[x].push_back(y);
        V[y].push_back(x);
    }

    fclose(f);
}

void DFS(int nod)
{
    viz[nod] = 1;
    for(int i = 0; i < V[nod].size(); ++i)
        if(!viz[V[nod][i]])
            DFS(V[nod][i]);
}

void solve(void)
{
    for(int i = 1; i <= N; ++i)
        if(!viz[i])
            DFS(i), ++cnt;
}

void print(void)
{
    FILE *g = fopen("dfs.out", "w");
    fprintf(g, "%d\n", cnt);

    fclose(g);
}
int main(void)
{
    read();
    solve();
    print();

    return 0;
}