#include <stdio.h>

int main() {
    printf("Rechne Zahl a in Zahlensystem zur Basis b um.\n");
    unsigned int a, b;
    printf("a = "); 
    if (scanf("%u", &a) != 1) return 1;
    printf("b = "); 
    if (scanf("%u", &b) != 1 || b < 2) return 2;
    char digits[64]; 
    unsigned int i = 0;
    while (a > 0) {
        unsigned int digit = a % b; 
        a /= b;
        if (digit < 10) {
            digit += '0';
        }
        else {
            digit = 'a' + digit - 10;
        }
        digits[i++] = digit;
    }
    // digits contains digits of a in numeral system b, 
    // but in reversed order!
    while (i-- > 0) {
        putchar(digits[i]);
    }
    putchar('\n');
}