#include <stdio.h>
#include <vector>
#include <deque>
#include <bitset>

using namespace std;
FILE* f, * g;

deque <int> q;
vector <int> graph[100002];
//bitset <100002> fr;
bool fr[100002];

void dfs(int nod)///dfs varianta iterativa
{
    q.push_back(nod);
    fr[nod] = 1;
    while (!q.empty())
    {
        nod = q.front();
        for (int i = 0;i < graph[nod].size();++i)
        {
            if (!fr[graph[nod][i]])
                fr[graph[nod][i]] = 1, q.push_back(graph[nod][i]);
        }
        q.pop_front();
    }
}
int main()
{
    int m, n, ss = 0;
    f = fopen("dfs.in", "r");
    g = fopen("dfs.out", "w");
    fscanf(f, "%d %d", &n, &m);
    int x, y;
    for (int i = 1;i <= m;++i)
    {
        fscanf(f, "%d %d", &x, &y);
        graph[x].push_back(y);
        graph[y].push_back(x);
    }
    for (int i = 1;i <= n;++i)
        if (!fr[i])
            ++ss, dfs(i);
    fprintf(g, "%d\n", ss);
    fclose(f);
    fclose(g);
    return 0;
}