var i,n: longint; begin write('Nhap so i: '); readln(i); if ((i=1) or (i=0)) then writeln('Day khong phai la so nguyen to') else begin for n:=2 to trunc(sqrt(i)) do if (i mod n = 0) then begin writeln('Day khong phai la so nguyen to'); break; end; if (n = trunc(sqrt(i))) then writeln('Day la so nguyen to'); end; readln end.
