#include <fstream>
#include <vector>
using namespace std;

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

typedef vector<int> VI;

int n, m, cnt;
vector<VI> A;
vector<bool> s;

void ReadGraph();
void DFS(int x);

int main()
{
    ReadGraph();
    for ( int i = 1; i <= n; i++ )
        if ( !s[i] ) DFS(i), cnt++;
    fout << cnt;
    fin.close();
    fout.close();
    return 0;
}

void DFS(int x)
{
    s[x] = true;
    for ( size_t i = 0; i < A[x].size(); i++ )
    {
        int y = A[x][i];
        if ( !s[y] ) DFS(y);
    }
}

void ReadGraph()
{
    fin >> n >> m;
    A = vector<VI>(n + 1);
    s = vector<bool>(n + 1, false);
    int x, y;
    for ( int i = 1; i <= m; i++ )
    {
        fin >> x >> y;
        A[x].push_back(y);
        A[y].push_back(x);
    }
}