program rival;
var a,b:array[1..100]of longint;
    t,k,m,n,i,j,x,y,max,tot:longint;
procedure sou(i,x,y,s:longint);
var t,k:longint;
begin
if i=n+1 then
  begin
    if s>max then
      max:=s;
    exit;
  end;
for t:=i to n do
  begin
    if x-b[t]>=0 then
      sou(t+1,x-b[t],y,s+a[t]);
    if y-b[t]*2>=0 then
      sou(t+1,x,y-b[t]*2,s+a[t]);
  end;
end;
begin
assign(input,'rival.in');
reset(input);
assign(output,'rival.out');
rewrite(output);
readln(x,y);
readln(n,m);
for t:=1 to n do
  readln(a[t],b[t]);
for t:=1 to n do
  begin
    if x-b[t]>=0 then
      sou(t+1,x-b[t],y,a[t]);
    if y-b[t]*2>=0 then
      sou(t+1,x,y-b[t]*2,a[t]);
  end;
for t:=1 to n do
  tot:=tot+a[t];
writeln(tot-max);
close(output);
end.