Program Lab51;

procedure Poisk(an:string);
var
 i:integer;
 Frst,Lst:Char;

begin
 i:=Length(an);
 Frst:=an[1];
 Lst:=an[i];
 Writeln('Pervaya cifra = ',Frst);
 Writeln('Poslednyaya cifra = ',Lst);
end;

var
 s:string;
 j,L:integer;
 b:boolean;

begin
 repeat
  b:=TRUE;
  Writeln('Cislo:');
  Readln(s);
  L:=Length(s);
  for j:=1 to L do
   if (Ord(s[j])<48) or (Ord(s[j])>57) then b:=FALSE;
  if b=FALSE then writeln('Eto ne chislo, povtorite vvod!');
 until b;
 Writeln;
 Poisk(s);
 Readln
end.