#include <vector>
#include <fstream>
#include <cstdlib>

using namespace std;

const int N_MAX=100011;

bool was[N_MAX];
vector<int> G[N_MAX];

inline void DFS(int x)
{
    was[x]=true;
    vector<int>::const_iterator it=G[x].begin(), iend=G[x].end();

    for(; it < iend; ++it)
        if(false == was[*it])
           DFS(*it);
}
int main()
{
    int N, M, x, y, count=0;
    ifstream in("dfs.in");
    ofstream out("dfs.out");

    for(in>>N>>M; M; --M)
    {
        in>>x>>y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    for(x=1; x <= N; ++x)
        if(false == was[x])
        {
            ++count;
            DFS(x);
        }
    out<<count<<'\n';

    return EXIT_SUCCESS;
}