#include <fstream>
#include <vector>

using namespace std;

ifstream fin("dfs.in");
ofstream fout("dfs.out");

int n,m,i,j,x,y,p,u;
int nrBFS,nodcurent,vecin,v[100001],C[100001];
vector <int> L[100001];

int main()
{
    fin >> n >> m;
    for (i=1; i<=m; i++)
    {
        fin >> x >> y;
        L[x].push_back(y);
        L[y].push_back(x);
    }
    for (i=1; i<=n; i++)
    {
        if (v[i] == 1)
            continue;
        nrBFS++;
        C[1] = i;
        p = 1; u = 1;
        v[i] = 1;
        while (p <= u)
        {
            nodcurent = C[p];
            for (j=0; j<L[nodcurent].size(); j++)
            {
                vecin = L[nodcurent][j];
                if (vecin != 0 && v[vecin] == 0)
                {
                    C[++u] = vecin;
                    v[vecin] = 1;
                }
            }
            p++;
        }
    }
    fout << nrBFS;
    return 0;
}