#include<fstream.h>
#include<stdlib.h>
#define dim 10001

int *a[dim],viz[dim],c[dim];
unsigned long n,i,m,j,prim,ultim,x,y;

int main()
{ifstream f("dfs.in");
ofstream g("dfs.out");

f>>n>>m;
for(i=1;i<=n;i++)
 {a[i]=(int*)realloc(a[i],sizeof(int));
  a[i][0]=0;
 }
for(i=1;i<=m;i++)
 {f>>x>>y;
  a[x][0]++;
  a[x]=(int*)realloc(a[x],a[x][0]*sizeof(int));
  a[x][a[x][0]]=y;
  a[y][0]++;
  a[y]=(int*)realloc(a[y],a[y][0]*sizeof(int));
  a[y][a[y][0]]=x;
 }
f.close();

unsigned long cont=0;
for(i=1;i<=n;i++)
 if(!viz[i])
   {cont++;
    c[0]=i;
    viz[i]=1;
    prim=ultim=0;
    while(prim<=ultim)
     {x=c[prim++];
      for(j=1;j<=a[x][0];j++)
       if(!viz[a[x][j]])
	{viz[a[x][j]]=1;
	 c[++ultim]=a[x][j];
	}
     }
   }

g<<cont<<'\n';
g.close();
return 0;
}