A tried a lot but wa#3 always shown!
I find the largest prime in the range,
If there isnt so I just use brute force.
I know that triviality(1)=0 ... but Why WA???

const
a:array[1..168] of longint=(
2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,
73,79,83,89,97,101,103,107,109,113,127,131,137,139,149,151,157,163,167
,173,
179,181,191,193,197,199,211,223,227,229,233,239,241,251,257,263,269,271
,277,281,
283,293,307,311,313,317,331,337,347,349,353,359,367,373,379,383,389,397
,401,409,
419,421,431,433,439,443,449,457,461,463,467,479,487,491,499,503,509,521
,523,541,
547,557,563,569,571,577,587,593,599,601,607,613,617,619,631,641,643,647
,653,659,
661,673,677,683,691,701,709,719,727,733,739,743,751,757,761,769,773,787
,797,809,
811,821,823,827,829,839,853,857,859,863,877,881,883,887,907,911,919,929
,937,941,947,953,967,971,977,983,991,997);

var
  m,n,minn,i,k:longint;
  y,min:real;

function prime(x:longint):boolean;
var
  j:longint;
begin
  for j:=1 to 168 do
  begin
    if a[j]>trunc(sqrt(x)) then
    begin
      prime:=true;
      exit;
    end;
    if x mod a[j]=0 then
    begin
      prime:=false;
      exit;
    end;
  end;
end;

function count(x:longint):longint;
var
  s,i:longint;
begin
  s:=1;
  for i:=2 to x-1 do
  if x mod i=0 then s:=s+i;
  count:=s;
end;

begin
  readln(n,m); if (n=1) or (m=1) then begin writeln(1); halt; end;
  if n=m then begin writeln(n); halt; end;

  for i:=m downto n do
  if prime(i) then begin writeln(i); halt; end;

  min:=2147483647;
  for i:=n to m do
  begin
    y:=count(i)/i;
    if y<min then begin min:=y; minn:=i; end;
  end;
  writeln(minn);
end.