var n:longint;
function checkprime(x:longint):boolean;
var c:longint;
begin
if x<2 then exit(false);
for c:=2 to trunc(sqrt(x)) do if x mod c = 0 then exit(false) else exit(true);
end;
begin
write('Nhap n: '); readln(n);
if checkprime(n) then write('Day la so nguyen to') else write('Day khong phai la so nguyen to');
readln;
end.