#include <fstream>
#include <cstdlib>

using namespace std;

void DFS (unsigned int node);

unsigned int N, M;
unsigned int X, Y;

unsigned int *A[100001];
bool seen[100001];
unsigned int i;

unsigned int sol;

int main ()
{
    ifstream fin ("dfs.in");
    fin >> N >> M;
    for (i=1; i<=N; i++)
    {
        A[i] = (unsigned int *) realloc (A[i], sizeof (unsigned int));
        A[i][0] = 0;
    }
    for (i=1; i<=M; i++)
    {
        fin >> X >> Y;
        A[X][0]++;
        A[X] = (unsigned int *) realloc (A[X], (A[X][0]+1) * sizeof (unsigned int));
        A[X][A[X][0]] = Y;
        A[Y][0]++;
        A[Y] = (unsigned int *) realloc (A[Y], (A[Y][0]+1) * sizeof (unsigned int));
        A[Y][A[Y][0]] = X;
    }
    fin.close();
    for (i=1; i<=N; i++)
        if (!seen[i])
        {
            sol++;
            DFS(i);
        }
    ofstream fout ("dfs.out");
    fout << sol;
    fout.close();
    return 0;
}

void DFS (unsigned int node)
{
    unsigned int i;
    seen[node] = 1;
    for (i=1; i<=A[node][0]; i++)
        if (!seen[A[node][i]])
            DFS(A[node][i]);
}