#include  <fstream>
#include  <vector>

std:: ifstream in("dfs.in");
std:: ofstream out("dfs.out");

const int NMAX=100005;
std:: vector <int> muchii[NMAX];

int vizit[NMAX],N,M;

void citire(){
in >> N >> M ;

for(int i =M;i>0;i-=1)
 {   int x,y;
    in >> x>>y;
muchii[x].push_back(y),muchii[y].push_back(x);
 }
}

void DFS(int nod){
vizit[nod]=1;
for(unsigned int i =0;i<muchii[nod].size();i++)
    if(!vizit[muchii[nod][i]])DFS(muchii[nod][i]);
}
int main(){
int c=0;
      citire();
for(int i=1;i<=N;i++)
   if(!vizit[i]){
       c++, DFS(i);
}
out<<c;
return 0;
}