#include <fstream>
#include <iostream>
#include <vector>
using namespace std;
ifstream f("dfs.in");
ofstream g("dfs.out");
int n, m, c[100002], nr, a, b;
vector< vector <int> > lv;
void citire()
{
f>>n>>m;
lv.resize(n+1);
for(int i=1;i<=m;i++){
f>>a>>b;
lv[a].push_back(b);
lv[b].push_back(a);
}
}

void DF(int x)
{
c[x]=1;
vector<int>::iterator it;
for(it=lv[x].begin();it!=lv[x].end();++it)
if(!c[*it])
DF(*it);
}

int main()
{
citire();
for(int i=1;i<=n;i++)
if(!c[i]) ++nr,DF(i);

g<<nr<<'\n';
g.close();

return 0;
}