#include<fstream.h>
ifstream f("dfs.in");
ofstream g("dfs.out");
int n, m, viz[100005], nr, x, y;
typedef struct nod
{int x;
 nod *urm;
} *graf;
graf v[100005];
void adaugare(graf &dest, int val)
{graf p;
 p = new nod;
 p -> x = val;
 p -> urm = dest;
 dest = p;
}
void citire()
{f>>n>>m;
 for (int i = 1; i <= m; i++)
	{f>>x>>y; adaugare(v[x], y); adaugare(v[y], x);}
}
void DFS(int k)
{graf p;
 viz[k] = 1;
 for (p = v[k]; p != NULL; p = p -> urm) if (!viz[p -> x]) DFS(p -> x);
}	
int main()
{citire();
 for (int i = 1; i <= n; i++) if (viz[i]==0) {nr++; DFS(i);}
 g<<nr<<"\n";
 return 0;
}