#include <fstream>
#define NMax 100001
using namespace std;

struct NOD  {
                int key;
                NOD *next;
            };

NOD *start[NMax];
bool vis[NMax];

void DF(int x)
{
    NOD *p;
    p = start[x];

    while(p)
    {
        if(! vis[p->key])
        {
            vis[p->key] = true;
            DF(p->key);
        }
        p = p->next;
    }
}

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

    int n, m, i, j, c, comp;
    NOD *p;

    fin >> n >> m;

    for(c=1 ; c<=m ; ++c)
    {
        fin >> i >> j;

        p = new NOD;
        p->key = j;
        p->next = start[i];
        start[i] = p;

        p = new NOD;
        p->key = i;
        p->next = start[j];
        start[j] = p;
    }

    comp = 0;
    for(c=1 ; c<=n ; ++c)
    {
        if(! vis[c])
        {
            ++comp;
            vis[c] = true;
            DF(c);
        }
    }

    fout << comp;

    return 0;
}