#include <stdio.h>
#include <math.h>
#include <stdlib.h>
#define BASE 9

long int BASEto10(long int a);
long int OBRATNO(long int b);
int main(void)
{
 long int x, y;
    long int n, m;
 printf("Ternary notation: (input only digits 0,1,2,3,4,5,6,7,8) a=");
 scanf("%ld", &x);
 y = BASEto10(x);
 printf("Decimal notation: a=%ld\n", y);
    printf("Input new decimal notation: b = ");
    scanf("%ld", &n);
    m = OBRATNO(n);
    printf("Ternary notation: b=%ld\n", m);
 return 0;
}
long int BASEto10(long int a) {
 int k=1;
 long int a10=0;
 while (a) {
 a10 += k*(a%10);
 k *= 9;
 a /= 10;
 }
 return a10;
}
long int OBRATNO(long int b)
{ //perevod iz 10 v 9
 int p=1;
 long int b9=0;
 while (b) {
 b9 += p*(b%9);
 p *= 10;
 b /= 9;
 }
 return b9;
}