#include <iostream>
#include <fstream>
#include <string.h>
#define N_MAX 10001

using namespace std;

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

short viz[N_MAX],G[N_MAX][N_MAX];
int n,m;

inline void Read()
{
    f >> n >> m;
    int x,y;
    for(int k = 1; k <= n; k++)
    {
        f >> x >> y;
        G[x][y] = G[y][x] = 1;
    }
    f.close();
}

void DFS(int nod)
{
    viz[nod] = 1;
    for(int k = 1; k <= n; k++)
        if(!viz[k] && G[nod][k])
            DFS(k);

}
int main()
{
    int p = 0;
    memset(viz,0,N_MAX);
    Read();
    for(int h = 1; h <= n; h++)
        if(!viz[h])
        {
            p++;
            DFS(h);
        }
    g << p;
    return 0;
}