Var
 st,s : string;
 x,y,i,j,fl : longint;
BEGIN
 Readln(st);
 if length(st) and 1 <> 0 then
  st := '0' + st;
 i := 3;
 j := length(st);
 val(copy(st,1,2),y,fl);
 y := (y mod 7)*2;
 while i < j do
  Begin
   s := copy(st,i,2);
   val(s,x,fl);
   y := ((x+y) mod 7) * 2;
   Inc(i,2);
  End;
 Writeln(y div 2);
END.