Program SNT;
Uses crt;
Var n: longint;

Function ngto(a:longint):boolean;
Var i: longint;
Begin
        If i<2 then exit(false);
        For i:=2 to n div 2 do
                If n mod i = 0 then exit(false);
                                    exit(true);
End;

Begin
        Clrscr;
        Write('Nhap n: '); Readln(n);
        If ngto(n) then Write(n,' la so nguyen to')
        Else Write(n,' khong phai la so nguyen to');
        Readln
End.

uses crt;

var n,i : integer;

kt: boolean;

begin

kt:=true;

write(‘nhap so can xet’); readln(n);

for i:=2 to n-1 do

if n mod i =0 then kt:=false;

if kt then write(n,’la so nguyen to)

else write(n,’khong phai la mot so nguyen to’);

readln

end.