uses crt;
var n,i,kt:integer;
begin
clrscr;
write('Nhap n='); readln(n);
if n>1 then 
begin
kt:=0;
for i:=2 to trunc(sqrt(n)) do 
  if n mod i=0 then kt:=1;
if kt=0 then writeln(n,' la so nguyen to')
else writeln(n,' khong phai la so nguyen to');
end
else writeln(n,' khong la so nguyen to ');
readln;
end.
end.

MINH HÙNG 6a2
uses crt;
var n,i,kt:integer;
begin
clrscr;
write('Nhap n='); readln(n);
if n>1 then 
begin
kt:=0;
for i:=2 to trunc(sqrt(n)) do 
  if n mod i=0 then kt:=1;
if kt=0 then writeln(n,' la so nguyen to')
else writeln(n,' khong phai la so nguyen to');
end
else writeln(n,' khong la so nguyen to ');
readln;
end.
end.