1.
uses crt;
var i,n,kt:longint; s:string;
begin
clrscr;
write('Nhap n: ');readln(n);
str(n,s);
for i:=2 to length(s) do
if s[i]<=s[i-1] then kt:=1;
writeln(kt=0);
readln
end.
2.
uses crt;
var i,n,kt,k:longint; s:string;
begin
clrscr;
write('Nhap n: ');readln(n);
str(n,s);
if s[1]<s[2] then kt:=1;
for i:=1 to n-1 do
if ((i mod 2=kt)and(s[i]>s[i+1]))or((i mod 2<>kt)and(s[i]<s[i+1])) then k:=1;
writeln(k=0);
readln
end.
3.
uses crt;
var n,i:longint;
begin
clrscr;
write('Nhap n: ');readln(n);
write(n,': ');
for i:=2 to n div 2 do
if n mod i=0 then write(i,' ');
readln
end.