const f = 'dfs.in'; g = 'dfs.out';

type pnod = ^nod;
     nod = record
        next : pnod;
        info : longint;
end;

var
    a : array[0..100001] of pnod;
    viz : array[0..100001] of longint;
    x, y, start, m, n : longint;
    nrc, i : longint;
    p : pnod;
    buf, buf1 : array[1..1 shl 17] of char;

procedure add( var dest : pnod; val : longint );
    var
        q : pnod;

    begin
        new( q );
        q^.info := val;
        q^.next := dest;
        dest := q;
    end;

procedure dfs( start : longint );
    var
        q : pnod;

    begin

        viz[start] := 1;
        q := a[start];

        while q <> nil do begin
            if viz[q^.info] = 0 then dfs( q^.info );
            q := q^.next;
        end;

    end;
begin
    assign( input,f ); reset( input );
    assign( output,g ); rewrite( output );
    settextbuf( input,buf );
    settextbuf( output,buf1 );
    readln(n, m );
    for i:=1 to m do begin
        readln(x, y);
        add( a[x], y );
        add( a[y], x );
    end;

    for i := 1 to n do
        if viz[i] = 0 then begin
            inc( nrc );
            dfs( i );
        end;

   writeln( nrc );
end.