#include <fstream>
#include <stdlib.h>

using namespace std;

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

int n, m, *A[100005], Valid[100005], nr;

void DFS(int x)
{
    int i;
    for (i=1; i<=A[x][0]; i++)
    {
        if (Valid[A[x][i]]==0)
        {
            Valid[A[x][i]]=1;
            DFS(A[x][i]);
        }
    }
}

int main()
{
    int i, x, y;
    fin>>n>>m;
    for (i=1; i<=n; i++)
    {
        A[i] = (int *) realloc(A[i], sizeof(int));
        A[i][0]=0;
    }
    for (i=1; i<=m; i++)
    {
        fin>>x>>y;
        A[x][0]++;
        A[x] = (int *) realloc(A[x], (A[x][0]+1)*sizeof(int));
        A[x][A[x][0]]=y;
        A[y][0]++;
        A[y] = (int *) realloc(A[y], (A[y][0]+1)*sizeof(int));
        A[y][A[y][0]]=x;
    }
    for (i=1; i<=n; i++)
    {
        if (Valid[i]==0)
        {
            nr++;
            DFS(i);
        }
    }
    fout<<nr;
    return 0;
}