#include <fstream>
#include <vector>
#define NMax 100005
using namespace std;
ifstream fin("dfs.in");
ofstream fout("dfs.out");
vector <int> G[NMax];
int N,M,Use[NMax],Sol;
void Read()
{
    fin>>N>>M;
    for(int i=1;i<=M;i++)
    {
        int x,y;
        fin>>x>>y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
}
void DFS(int nod)
{
    Use[nod]=1;
    for(unsigned int i=0;i<G[nod].size();i++)
        {
            int nodnou=G[nod][i];
            if(!Use[nodnou])
                DFS(nodnou);
        }
}
void Print()
{
   fout<<Sol<<'\n';
}
int main()
{
    int i;
    Read();
    for(i=1;i<=N;i++)
    {
      if(!Use[i])
        {
        Sol++;
        DFS(i);
        }
    }
    Print();
    return 0;
}