#include <cstdio>
#include <vector>

using namespace std;

const int MAX = 100003;

vector<int> v[MAX];
int n, m;
bool viz[MAX];

void dfs(int nod);

int main()
{
    freopen("dfs.in", "r", stdin);
    freopen("dfs.out", "w", stdout);
    int a, b, nrComp=0;
    scanf("%d%d", &n, &m);
    for(int i=1; i<=n; i++)
    {
        scanf("%d%d", &a, &b);
        v[a].push_back(b);
        v[b].push_back(a);
    }
    for(int i=1; i<=n; i++)
    {
        if(!viz[i])
        {
            nrComp++;
            dfs(i);
        }
    }
    printf("%d\n", nrComp);
    return 0;
}
void dfs(int nod)
{
    int fiu;
    vector<int>::iterator it;
    for(it=v[nod].begin(); it!=v[nod].end(); ++it)
    {
        fiu = *it;
        if(!viz[fiu])
        {
            viz[fiu] = 1;
            dfs(fiu);
        }
    }
}