#include <fstream>
#include <vector>
using namespace std;
ifstream fin("dfs.in");
ofstream fout("dfs.out");

int n, m, ans;
bool viz[100001];
vector <int> v[100001];

void Read()
{
    fin >> n >> m;
    int x, y;
    for(int i = 1; i <= m; ++ i)
    {
        fin >> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
}

void dfs(int x)
{
    viz[x] = 1;
    int cnt = v[x].size();
    for(int i = 0; i < cnt; ++ i)
        if(viz[v[x][i]] == 0)
            dfs(v[x][i]);
}

int main()
{
    Read();

    for(int i = 1; i <= n; ++ i)
        if(viz[i] == 0)
        {
            dfs(i);
            ans ++;
        }

    fout << ans << '\n';
    return 0;
}