#include <fstream>
#include <vector>
using namespace std;
ifstream fin("dfs.in");
ofstream fout("dfs.out");
const int NMax = 100000;
vector <int> G[NMax + 5];
int N,M,Sol;
bool Use[NMax + 5];
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(auto Vecin : G[Nod])
    {
        if(!Use[Vecin])
            DFS(Vecin);
    }
}

void Print()
{
    fout << Sol << "\n";
}

int main()
{
    Read();
    for(int i = 1; i <= N; ++i)
        if(!Use[i])
        {
            Sol++;
            DFS(i);
        }

    Print();
    return 0;
}