#include <fstream>
#include <vector>
#define NMax 100003
using namespace std;
ifstream fin("dfs.in");
ofstream fout("dfs.out");
int N,M;
vector <int> G[NMax];
int 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)
{
    vector <int> :: iterator it;
    Use[nod]=1;
    for(it=G[nod].begin();it!=G[nod].end();it++)
        if(!Use[*it])
            DFS(*it);
}

void DFS1(int nod)
{
    unsigned int i;
    Use[nod]=1;
    for(i=0;i<=G[nod].size();i++)
        {
            int Vecin=G[nod][i];
            if(!Use[Vecin])
                DFS(Vecin);
        }
}

int main()
{
    Read();
    for(int i=1;i<=N;i++)
    {
        if(!Use[i])
        {
            Sol++;
            DFS(i);
        }
    }
    fout<<Sol<<'\n';
    return 0;
}