// http://infoarena.ro/problema/dfs
#include <fstream>
#include <vector>
using namespace std;

const int MAXSIZE = 100001;

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

int nodes,edges,answer;
bool visited[MAXSIZE];
vector<int> graph[MAXSIZE];

void depthFirst(int node);

int main()
{
    in >> nodes >> edges;

    int from,to;
    for(int i=1;i<=edges;i++)
    {
        in >> from >> to;

        graph[from].push_back(to);
        graph[to].push_back(from);
    }
    in.close();

    for(int i=1;i<=nodes;i++)
        if(!visited[i])
        {
            depthFirst(i);
            answer++;
        }

    out << answer << "\n";
    out.close();

    return (0);
}

void depthFirst(int node)
{
    vector<int>::iterator end = graph[node].end();
    visited[node] = true;

    for(vector<int>::iterator it=graph[node].begin();it!=end;++it)
        if(!visited[*it])
            depthFirst(*it);
}