uses crt;
var s:string[100]; i:longint;
begin
clrscr;
   write('s=');readln(s);
   write('A. ');
   for i:=length(s) downto 1 do write(s[i]); writeln;
   writeln('B. ',copy(s,6,length(s)-5));
   for i:=1 to length(s) do if s[i]='N' then s[i]:='g';
   writeln('C. ',s);
   write('D. ');
   for i:=1 to length(S) do if upcase(s[i]) in ['A'..'Z'] then write(s[i]);
readln
end.

Program hotrotinhoc;

var st,s: string;

i,n: integer;

begin

write('Nhap xau : '); readln(st);

writeln('Xau vua nhap la : ',st);

 s:=st;

writeln('Do dai cua xau la : ',length(st));

while st[1]=#32 do delete(st,1,1);

while st[length(st)]=#32 do delete(st,length(st),1);

while pos(#32#32,st)<>0 do delete(st,pos(#32#32,st),1);

writeln('Xau sau khi xoa cac ky tu trang : ',st);

s:=upcase(s);

writeln('Xau sau khi bien doi thanh xau in hoa : ',s);

s:=lowercase(s);

write('Xau sau khi bien doi thanh xau in thuong : ',s);

readln

end.