data entry error..!!

Can somebody please tell me what to put in my code for positive integer division if someone enters a negative number...??  This is my code:

/*integer division using 2 positive integers
*/

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

{
      main ()

      int dividend = N;
      int didvisor = D;
      int quotient = Q;
      int remainder = R;

      printf("Enter a positive whole number to be used as the dividend");
      scanf("%d", &N);
      printf("Enter a positive whole number to be used as the divisor");
      scanf("%d", &D);

      //perform the integer division
      Q = N/D;
      printf("\n The quotient is %d", Q);

      //perform the modulus
      R = N%D;
      printf(("\n The remainder is %d", R);
      return 0;
}