#include <bits/stdc++.h>

using namespace std;

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

int n,m;
vector<int> viz;
vector<vector<int>> v;

void Read()
{
    f>>n>>m;
    v.resize(n+1);
    viz.resize(n+1);
    for(int i=1;i<=m;i++)
    {
        int x,y;
        f>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    f.close();
}

void Dfs(int nod,int contor)
{
    viz[nod] = contor;
    for(auto& vecin : v[nod])
    {
        if(!viz[vecin])
            Dfs(vecin,contor);
    }
}

void Solve()
{
    Dfs(1,1);
    int contor=1;
    for(int i=1;i<=n;i++)
    {
        if(!viz[i])
        {
            contor++;
            Dfs(i,1);
        }
    }
    g<<contor;
}
int main()
{
    Read();
    Solve();
    return 0;
}