using namespace std;
#include<fstream>
#include <vector>

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

const int NMax = 100005;

vector <int> G[NMax];
int Use[NMax];
int N,M,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(int i = 0; i < (int)G[Nod].size(); ++i)
        {
            int Vecin = G[Nod][i];
            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;
}