#include <cstdio>
#include <vector>
#define NMAX 100004

using namespace std;

FILE*fin=fopen("dfs.in", "r");
FILE*fout=fopen("dfs.out", "w");

int n, m;
vector <int> A[NMAX];//matrice de adiacenta
bool uz[NMAX];

void citire();
void dfs(int vf);

int main()
{
    int i, nr=0;
    citire();
    for(i=1;i<=n;i++)
        if(!uz[i])
        {
            dfs(i);
            ++nr;
        }
    fprintf(fout, "%d\n", nr);
    return 0;
}

void citire()
{
    int i, x, y;
    fscanf(fin, "%d %d", &n, &m);
    for(i=1;i<=m;i++)
    {
        fscanf(fin, "%d %d", &x, &y);
        A[x].push_back(y);
        A[y].push_back(x);
    }
}

void dfs(int vf)
{
    int i, lg;

    uz[vf]=1;
    lg=A[vf].size();

    for(i=0;i<lg;i++)
        if(!uz[A[vf][i]])
            dfs(A[vf][i]);
}