#include <fstream>
#include <set>
#include <bitset>

using namespace std;

ifstream cin("dfs.in");
ofstream cout("dfs.out");

int n,m,cnt;
set <int> v[100001];
bitset <100001> f;

void dfs (int x)
{
    f[x]=1;
    for (auto i : v[x])
        if (f[i]==0)
            dfs(i);
}

int main()
{
    cin>>n>>m;
    for (int i=1; i<=m; i++)
    {
        int x,y;
        cin>>x>>y;
        v[x].insert(y);
        v[y].insert(x);
    }
    for (int i=1; i<=n; i++)
        if (f[i]==0)
        {
            cnt++;
            dfs(i);
        }
    cout<<cnt;
}