#include<fstream>
#include<cstdio>
#include<set>
#include<vector>
#include<algorithm>
#define FOR(a,b,c) for(int a=b;a<=c;++a)
#include<cstring>
#include<bitset>
#include<cmath>
#include<iomanip>
#include<queue>
#define f cin
#define g cout
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define mod 1000000007
#define ll unsigned long long
#define bit (1<<18)
#define inf 500000000
#define N 100100
#define mod  1999999973
#define inu "dfs.in"
#define outu "dfs.out"
using namespace std;
ifstream f(inu);
ofstream g(outu);
//int dx[]={0,0,0,1,-1};
//int dy[]={0,1,-1,0,0};
vector<int> v[N];
int x,y,n,m,sol,viz[N];
void dfs(int x)
{
	viz[x]=1;
	for(int i=0;i<v[x].size();++i)
		if(!viz[v[x][i]])
			dfs(v[x][i]);
}

int main ()
{
	f>>n>>m;
	FOR(i,1,m)
	{
		f>>x>>y;
		v[x].push_back(y);
		v[y].push_back(x);
	}
	FOR(i,1,n)
	{
		if(!viz[i])
		{
			sol++;
			dfs(i);
		}
	}
	g<<sol;
	return 0;
}