#include <fstream>
#include <stack>
#include <vector>

using namespace std;

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

bool visit[100001];
vector<int> a[100001]; //adiacenta
stack<int> stk;

void dfs(int start)
{
    int top;
    //vector <int> :: iterator it;
    stk.push(start);
    visit[start] = true;
    while (!stk.empty())
    {
        top = stk.top();
        stk.pop();
        for (int i = 0; i < a[top].size(); i++)
        {
            if (visit[a[top][i]] == false)
            {
                visit[a[top][i]] = true;
                stk.push(a[top][i]);
            }
        }
    }
}
int nr;
int main()
{
    int n, m, x, y;
    fin >> n >> m;
    for (int i = 1; i <= m; i++)
    {
        fin >> x >> y;
        a[x].push_back(y);
        a[y].push_back(x);
    }

    for (int i = 1; i <= n; i++)
        visit[i] = false;

    for (int i = 1; i <= n; i++)
    {
        if (visit[i] == false)
        {
            dfs(i);
            nr++;
        }
    }
    fout << nr;
    return 0;
}