#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,con;
bool used[NMAX];

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 node)
{
    used[node]=true;
    for(unsigned int i=0;i<G[node].size();++i)
    {
        int vecin=G[node][i];
        if(!used[vecin])
            DFS(vecin);
    }
}

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