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

const int MAXN = 100003;

int N, M;
vector < int > v[MAXN];
bitset < MAXN > visited;

void readInput() {
    ifstream fin("dfs.in");

    fin >> N >> M;
    for ( int i = 0; i < M; ++i ) {
        int x, y;
        fin >> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
    }

    fin.close();
}

void DFS( int node ) {
    visited[node] = true;

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

/*
    for ( int i = 0; i < v[node].size(); ++i ) {
        int nextNode = v[node][i];
        if ( !visited[nextNode] )
            DFS( nextNode );
    }
*/
}

void findSolution() {
    int compConexe = 0;

    for ( int i = 1; i <= N; ++i ) {
        if ( !visited[i] ) {
            DFS(i);
            ++compConexe;
        }
    }

    ofstream fout("dfs.out");
    fout << compConexe;
    fout.close();
}

int main() {

    readInput();
    findSolution();

    return 0;
}