program test;
uses crt;
type
zv=^pointer;
pointer=record
elem:char;
next:zv;
end;
var
vlan1, vlan2, s1, s2:zv;
sym:char;
Lk,ls:boolean;

procedure vstav(lanka:zv; buk:char);
var
q:zv;
begin
new(q);
q^.elem:=buk;
q^.next:=lanka^.next;

lanka^.next:=q;
end;
begin
clrscr;
new(s1);
s1^.next:=nil;
vlan1:=s1;

write('enter symbols= ');
repeat
read(sym);
vstav(vlan1,sym);
vlan1:=vlan1^.next
until sym='.';
vlan1:=s1^.next;
writeln;
write('string S1= ');
while vlan1<>nil do
begin
if vlan1^.elem='k' then
lk:=true;
if (vlan1^.elem='s') and (lk=true) then
ls:=true;
write(vlan1^.elem);
vlan1:=vlan1^.next;
end;
writeln;

if (lk=true) and (ls=true) then
  begin
new(s2);
s2^.next:=nil;
vlan2:=s2;
vlan1:=s1^.next;

repeat
if vlan1^.elem='k' then
begin
vlan1:=vlan1^.next;
while vlan1^.elem<>'s' do
begin
vstav(vlan2,vlan1^.elem);
vlan2:=vlan2^.next;
vlan1:=vlan1^.next;
end;
end;

vlan1:=vlan1^.next
until vlan1=nil;

write('string S2= ');
vlan2:=s2;
vlan2:=vlan2^.next;
while vlan2<>nil do
begin
write(vlan2^.elem);
vlan2:=vlan2^.next;
end;
end
else writeln ('there are no k-s pairs in the S1 string');
end.