#include <iostream>
#include <stdio.h>
#include <vector>
#include <stack>

using namespace std;

int N, M;
int cc[100001];

void dfs(int nod, vector<vector<int> > vec, int nr_cc)
{
    cc[nod] = nr_cc;
    stack<int> stiva;
    stiva.push(nod);
    while(!stiva.empty())
    {
        nod = stiva.top();
        stiva.pop();
        int nr_vec = vec[nod].size();
        for(int i = 0; i < nr_vec; i++)
            if(cc[vec[nod][i]] == 0)
            {
                cc[vec[nod][i]] = nr_cc;
                stiva.push(vec[nod][i]);
            }
    }
}

int main()
{
    FILE *f = fopen("dfs.in", "r");
    FILE *g = fopen("dfs.out", "w");
    fscanf(f, "%d %d", &N, &M);
    vector<int> aux;
    vector<vector<int> > vecini(N + 1, aux);
    for(int i = 0; i < M; i++)
    {
        int x, y;
        fscanf(f, "%d %d", &x, &y);
        vecini[x].push_back(y);
        vecini[y].push_back(x);
    }
    int nr_cc = 0;
    for(int i = 1; i <= N; i++)
        if(cc[i] == 0)
        {
            nr_cc += 1;
            dfs(i, vecini, nr_cc);
        }
    fprintf(g, "%d\n", nr_cc);
    fclose(f);
    fclose(g);

    return 0;
}