program gota;
var
  fin,fout:text;
  a:array[1..3,1..2] of integer;
  i,j,s,p,q:integer;

procedure search(ss,pp,t:integer);
var
  k:integer;
begin
  k:=0;
  repeat
    inc(k);
    if (pp+a[k,2])>=0 then
    begin
      ss:=ss-a[k,1];
      pp:=pp+a[k,2];
      if ss<=0 then
      begin 
        if q>t then q:=t;
      end
      else search(ss,pp,t+1);
      ss:=ss+a[k,1];
      pp:=pp-a[k,2];
    end;
  until k>=3;
end;
    
begin
  assign(fin,'gota.in');
  assign(fout,'gota.out');
  reset(fin);
  rewrite(fout);  
  
  read(fin,s,p);
  q:=0;
  a[1,1]:=1;a[1,2]:=1;
  a[2,1]:=5;a[2,2]:=-2;
  a[3,1]:=10;a[3,2]:=-5;
  search(s,p,1);
  writeln(fout,q);

  close(fin);
  close(fout);
end.