#include <stdio.h>
#include <string.h>

static char trad[] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'};

int traduccion(char c, unsigned short B) {
    for (int i = 0; i < B; i++) {
        if (trad[i] == c) return i;
    }
    return -1;
}

unsigned int BaseLoad(char *S, unsigned short B) {
    unsigned int valor = 0;
    int len = strlen(S) - 1;
    unsigned int mult = 1;
    for (; len >= 0; --len) {
        int aux = traduccion(S[len], B);
        if (aux == -1) return 0;
        valor += aux * mult;
        mult *= B;
    }
    return valor;
}

int main() {
    printf("%d\n", BaseLoad("AB124FF", 16));
}