VAR
 N:LongInt;
BEGIN
 Write('N= ');
 Readln(N);
 If N=0 then
  Writeln('1')
 else
  Writeln(TRUNC(Ln(N)/Ln(10))+1);
 Readln;
END.

VAR
 Hmin,Hmax,Mmin,Mmax,Gong,H:Byte;
 M:ShortInt;
BEGIN
 Writeln('Enter Hmin, Mmin, Hmax, Mmax');
 Readln(Hmin, Mmin, Hmax, Mmax);
 Gong:=0;
 If Mmin=0 then
  begin
   If Hmin>12 then Inc(Gong,Hmin-12) else Inc(Gong,Hmin);
   M:=0;
  end
 else
  M:=Mmin-1;
 H:=Hmin;
 Repeat
  Inc(M);
  If M=30 then Inc(Gong);
  If M=60 then
   begin
    Inc(H);
    If H>24 then Dec(H,24);
    If H>12 then Inc(Gong,H-12) else Inc(Gong,H);
    M:=0;
   end;
 Until (H=Hmax) and (M=Mmax);
 Writeln(Gong);
 Readln;
END.

VAR
 A,B,i:LongInt;
 Num:Word;

Function Primzahl(Z:LongInt):Boolean;
var
 j:LongInt;
 b:boolean;
begin
 b:=true;
 j:=1;
 repeat
  Inc(j);
  if (Z mod j)=0 then b:=false;
 until (Not(b)) or (j=(Z div 2));
 Primzahl:=b;
end;

Function Inv(Z:LongInt):LongInt;
var
 S,S1:String;
 code:Integer;
 Z1:LongInt;
 j:Byte;
begin
 STR(Z,S);
 S1:=S;
 For j:=1 to Length(S) do
  S1[j]:=S[Length(S)-j+1];
 VAL(S1,Z1,Code);
 Inv:=Z1;
end;

BEGIN
 Writeln('Enter A, B');
 Readln(A, B);
 Num:=0;
 For i:=A to B do
  If (Primzahl(i)) and (Primzahl(Inv(i))) then Inc(Num);
 Writeln(Num);
 Readln;
END.