program MayLava;
type
 rec=record
  o2,n2,m:longint;
 end;
var
 q:array[1..1000]of rec;
 oo,nn,n,min:longint;
procedure start;
 var
  i,j:longint;
  f:text;
 begin
  assign(f,'ple.in');
  reset(F);
  readln(f,oo,nn);
  readln(f,n);
  for i:=1 to n do
   readln(f,q[i].o2,q[i].n2,q[i].m);
  close(f);
  min:=maxlongint;
 end;
procedure hunt(mt,ot,nt,t:longint);
 begin
  if mt>min then exit;
  if t>n then exit;
  if (ot>oo) and (nt>nn) and (mt<min) then begin
   min:=mt;
   exit;
  end;
  hunt(mt+q[t].m,ot+q[t].o2,nt+q[t].n2,t+1);
  hunt(mt,ot,nt,t+1);
 end;
procedure print;
 var
  f:text;
 begin
  assign(f,'ple.out');
  rewrite(f);
  writeln(f,min);
  close(f);
 end;
BEGIN
 start;
 hunt(0,0,0,1);
 print;
END.