program kakamaka;
var f,g:text;
    n,m,i,x,y:longint;
    a:array of array of longint;
    nr:longint;
    viz:array [1..100000] of 0..1;
    bufin,bufout:array [1..65000] of byte;

procedure df(nod:longint);
var i:longint;
begin
  for i:=1 to a[nod,0] do
   if viz[a[nod,i]]=0 then
   begin
    viz[a[nod,i]]:=1;
    df(a[nod,i]);
   end;
end;

begin
 assign (f,'dfs.in'); reset (f);
 assign (g,'dfs.out'); rewrite (g);
 settextbuf (f,bufin);
 settextbuf (g,bufout);
 readln (f,n,m);
 setlength (a,n+1,1);
 for i:=1 to m do
 begin
   readln (f,x,y);
   setlength (a[x],length (a[x])+1);
   a[x,0]:=a[x,0]+1;
   a[x,a[x,0]]:=y;
   setlength (a[y],length (a[y])+1);
   a[y,0]:=a[y,0]+1;
   a[y,a[y,0]]:=x;
 end;
 for i:=1 to n do
  if viz[i]=0 then
  begin
   inc(nr);
   viz[i]:=1;
   df(i);
  end;
  write (g,nr);
  close (f); close (g);
end.