program bs(input,output);
var
 co,cx,mo,mx:longint;
 ml:longint;
 ans,i,j,p:longint;
 f:array[1..2000000]of longint;

begin
 assign(input,'bs.in');
 reset(input);
 assign(output,'bs.out');
 rewrite(output);

 while not(eof) do
 begin
  readln(co,cx,mo,mx);
  if (mo=0)and(mx=0) then ans:=0
   else if (mo=0) then ans:=mx
    else if (mx=0) then ans:=mo
     else if (cx=co)and(mx>0)and(mo>0) then ans:=co+cx
  else
  begin
   ml:=mo+mx;
   if co>cx then
   begin
    p:=mx;
    mx:=mo;
    mo:=p;
    p:=co;
    co:=cx;
    cx:=p;
   end;
   for i:=1 to co do
   begin
    f[i*2]:=1;
    f[i*2-1]:=1;
   end;
   f[co*2+1]:=1;
   cx:=cx-co-1;
   for i:=1 to (co+1) do
   begin
    if cx>mx then
    begin
     f[i*2-1]:=mx;
     cx:=cx-mx+1;
    end
    else
    begin
     f[i*2-1]:=cx+1;
     break;
    end;
   end;

   ans:=0;
   for i:=1 to 2*co+1 do
    ans:=ans+f[i];
   for i:=1 to 2*co+1 do f[i]:=0;
  end;

  writeln(ans);
 end;

 close(input);
 close(output);
end.