#include <iostream>
#include <vector>
#include <fstream>
#include <queue>
using namespace std;
ifstream in("dfs.in");
ofstream out("dfs.out");

void dfs(int nod,vector <vector<int>> Graf,vector <int> &dist)
{
    dist[nod]=1;
    for(auto i: Graf[nod])
    {
        if(dist[i]==0)
            dfs(i,Graf,dist);
    }
}
int main()
{
    int n,m;
    int inf=10000;
    in>>n>>m;
    vector <vector<int>> Graf(n+1);
    vector <int>dist(n+1,0);
    for(int i=0;i<m;i++)
    {
        int x,y;
        in>>x>>y;
        Graf[x].push_back(y);
        Graf[y].push_back(x);
    }
    int term=0;
    int nr_comp=0;
    while(term==0)
    {
        term=1;
        int i;
        for(i=1;i<=n;i++)
        {
            if(dist[i]==0)
            {
                term=0;
                break;
            }
        }
        if(term==0)
        {
            dfs(i,Graf,dist);
            nr_comp++;
        }
    }
    out<<nr_comp;
    return 0;
}