#include <stdio.h>
int main ()
{
    char mystrings[8][5] = { {"ABC"},{"DEF"},{"GHI"},{"JKL"},{"MNO"},
                             {"PQRS"},{"TUV"},{"WXYZ"} };
    int i=0,j=0,k=0;
    int num;
    int leftdigit, middigit, rightdigit;

    printf("Enter a number (3-digit): ");
    scanf("%d", &num);
    printf("\n");

    if (num%10 == 0 || num%10 == 1)
       printf("Invalid input! The number should not contain 0 or 1.\n\n");
    else if (((num/10)%10 == 0) || ((num/10)%10 == 1))
       printf("Invalid input! The number should not contain 0 or 1.\n\n");
    else if (((num/100)%10 == 0) || ((num/100)%10 == 1))
       printf("Invalid input! The number should not contain 0 or 1.\n\n");
    else
      {
        printf("The combinations are:\n");
        leftdigit=num/100-2;
        middigit=(num/10)%10-2;
        rightdigit=num%10-2;

        for(i=0;i<=4;i++)
          {
            printf("%c", mystrings[leftdigit][i]);
            for(j=0; j<=4;j++)
             {
               printf("%c", mystrings[middigit][j]);
               for(k=0;k<=4;k++)
                 printf("%c", mystrings[rightdigit][k]);
             }
           printf(", ");
          }
      }

    system("PAUSE");
    return 0;
}