#include<fstream>
#include<vector>
#include<cstring>
using namespace std;
ifstream fin("dfs.in");
ofstream fout("dfs.out");
vector <int> G[100003];
int visit[100003],coada[100003];
void citire(int &n,int &m)
{
    fin>>n>>m;
    for(int i=1;i<=m;i++)
    {
        int x,y;
        fin>>x>>y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
}

void BFS(int nod)
{
    int l=1,r=1;
    coada[1]=nod;
    while(l<=r)
    {
        for(int j=0;j<G[coada[l]].size();j++)
            if(visit[G[coada[l]][j]]==0)
        {
            visit[G[coada[l]][j]]=1;
            r++;
            coada[r]=G[coada[l]][j];
        }
        l++;
    }
}
int main()
{
    int n,m,sol=0;
    citire(n,m);
    for(int i=1;i<=n;i++)
        if(visit[i]==0)
        {
            BFS(i);
            sol++;
            memset(coada,0,sizeof(coada));
        }
        fout<<sol;
}