program Project2;

{$APPTYPE CONSOLE}

uses
  SysUtils;

Var N,M,k,j:int64;
begin
readln(N,M);
assign(input,'legacy.in');
reset(input);
close(input);
if (N>M) then N:=a
if (N-M>0) then N-M:=b
readln(a,b);
if 
assign(output,'legacy.out');
rewrite(output);


close(output);
  { TODO -oUser -cConsole Main : Insert code here }
end.