#include <iostream>
#include <fstream>
#include<vector>
using namespace std;
ifstream f ("dfs.in");
ofstream g ("dfs.out");
int n,m,nr;
bool viz[100001];
vector<int>adiacenta[100001];
void DFS(int x)
{
    viz[x] = 1;
    for(auto vecin:adiacenta[x])
    {
        if(!viz[vecin])
            DFS(vecin);
    }
}
int main()
{
    f >> n >> m;
    for(int i = 1;i<=m;i++)
    {
        int x,y;
        f >> x >> y;
        adiacenta[x].push_back(y);
        adiacenta[y].push_back(x);
    }
    for(int i = 1;i<=6;i++)
    {
        if(!viz[i])
        {
            DFS(i);
            nr++;
        }
    }
    g << nr;
}