const
ss:array[1..169] 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,
179,181,191,193,197,199,211,223,227,229,233,239,241,251,257,263,269,27
1,277,281,
283,293,307,311,313,317,331,337,347,349,353,359,367,373,379,383,389,39
7,401,409,
419,421,431,433,439,443,449,457,461,463,467,479,487,491,499,503,509,52
1,523,541,
547,557,563,569,571,577,587,593,599,601,607,613,617,619,631,641,643,64
7,653,659,
661,673,677,683,691,701,709,719,727,733,739,743,751,757,761,769,773,78
7,797,809,
811,821,823,827,829,839,853,857,859,863,877,881,883,887,907,911,919,92
9,937,941,
947,953,967,971,977,983,991,997,0);
var
  a:array[1..169] of longint;
  i,j,k,x,y:longint;
function judge(m:longint):boolean;
var
  i,j,k,n,q:longint;
begin
  n:=m;
  fillchar(a,sizeof(a),0);
  judge:=false;
  i:=1;
  while (n>1)and(i<169) do begin
    while n mod ss[i]=0 do begin
      inc(a[i]);
      n:=n div ss[i];
    end;
    inc(i);
  end;
  if n>1 then begin ss[169]:=n;a[169]:=1;end;
  k:=1;
  for i:=1 to 169 do if a[i]>0 then begin
    q:=1;
    for j:=1 to a[i] do q:=q*ss[i]+1;
    if m*2<k*q then exit;
    k:=k*q;
  end;
  judge:=true;
end;

begin
  readln(x,y);
  for i:=x to y do
    if judge(i) then begin writeln(i);break;end;
end.